diff --git a/Makefile.mak b/Makefile.mak
index b3ceaf8b..2d92d806 100644
--- a/Makefile.mak
+++ b/Makefile.mak
@@ -47,12 +47,12 @@ bin\Pipeline\grzview.com: Pipeline\grzview.cpp th01\formats\grz.cpp
 bin\th01\zunsoft.com: th01\zunsoft.c
 	$(CC) $(CFLAGS) -mt -lt -nbin\th01\ $** masters.lib
 
-bin\th01\op.exe: bin\th01\op.obj th01\op_02.c th01\op_03.c th01\op_04.c th01\op_05.c th01\op_06.cpp th01\op_08.c th01\op_09.cpp th01\op_10.c th01\op_11.c th01\op_12.cpp
+bin\th01\op.exe: bin\th01\op.obj th01\op_02.c th01\op_03.c th01\op_04.c th01\op_05.c th01\op_06.cpp th01\op_07.cpp th01\op_08.c th01\op_09.cpp th01\op_10.c th01\op_11.c th01\op_12.cpp
 	$(CC) $(CFLAGS) -ml -3 -DGAME=1 -DBINARY='O' -nbin\th01\ -eOP.EXE @&&|
 $**
 |
 
-bin\th01\reiiden.exe: bin\th01\reiiden.obj th01\main_02.c th01\main_03.c th01\main_04.c th01\main_05.c th01\main_06.cpp th01\main_08.cpp th01\main_12.c th01\main_13.c th01\main_14.c th01\main_16.c
+bin\th01\reiiden.exe: bin\th01\reiiden.obj th01\main_02.c th01\main_03.c th01\main_04.c th01\main_05.c th01\main_06.cpp th01\main_07.cpp th01\main_08.cpp th01\main_12.c th01\main_13.c th01\main_14.c th01\main_16.c
 	$(CC) $(CFLAGS) -ml -3 -DGAME=1 -DBINARY='M' -nbin\th01\ -eREIIDEN.EXE @&&|
 $**
 |
diff --git a/th01/formats/ptn.hpp b/th01/formats/ptn.hpp
index 84db3968..5e60e46c 100644
--- a/th01/formats/ptn.hpp
+++ b/th01/formats/ptn.hpp
@@ -2,7 +2,8 @@
 /// -----------------------------------------
 /// Provides functions for both 32×32 and 16×16 sprites, and optionally
 /// supports transparency for images loaded from .PTN files, hardcoded to
-/// color #15.
+/// color #15. Can also be used to store the backgrounds of frequently updated
+/// VRAM regions, using the functions for raw allocation and VRAM snapping.
 
 #define PTN_W 32
 #define PTN_H 32
@@ -76,6 +77,10 @@ static inline ptn_t* ptn_with_id(int id)
 // Displays the given [ptn_id] at (⌊left/8⌋*8, top), disregaring its alpha
 // plane.
 void ptn_put_noalpha_8(int left, int top, int ptn_id);
+
+// Overwrites the 4 color planes of [ptn_id] with the current VRAM content of
+// the 32×32 pixels starting at (⌊left/8⌋*8, top).
+void ptn_snap_8(int left, int top, int ptn_id);
 // ------------
 
 // 16×16 access
@@ -103,5 +108,9 @@ struct PTNQuarter
 // Displays the given [quarter] of the given [ptn_id] at (⌊left/8⌋*8, top),
 // diregarding its alpha plane.
 void ptn_put_quarter_noalpha_8(int left, int top, int ptn_id, int quarter);
+
+// Overwrites the 4 color planes of the given [quarter] of [ptn_id] with the
+// current VRAM content of the 16×16 pixels starting at (⌊left/8⌋*8, top).
+void ptn_snap_quarter_8(int left, int top, int ptn_id, int quarter);
 // ------------
 /// -----------------------------------------
diff --git a/th01/formats/ptn_snap.cpp b/th01/formats/ptn_snap.cpp
new file mode 100644
index 00000000..bfaf24cd
--- /dev/null
+++ b/th01/formats/ptn_snap.cpp
@@ -0,0 +1,60 @@
+extern "C" {
+
+#include "th01/formats/ptn.hpp"
+
+void ptn_snap_8(int left, int top, int ptn_id)
+{
+	unsigned int vram_offset = vram_offset_muldiv(left, top);
+	ptn_t *ptn = ptn_with_id(ptn_id);
+	for(int y = 0; y < PTN_H; y++) {
+		#define snap(ptn, vram_offset, w) \
+			ptn->planes.B[y] = VRAM_CHUNK(B, vram_offset, w); \
+			ptn->planes.R[y] = VRAM_CHUNK(R, vram_offset, w); \
+			ptn->planes.G[y] = VRAM_CHUNK(G, vram_offset, w); \
+			ptn->planes.E[y] = VRAM_CHUNK(E, vram_offset, w);
+		snap(ptn, vram_offset, PTN_W);
+		#undef snap
+		vram_offset += ROW_SIZE;
+	}
+}
+
+static inline ptn_dots_t dot_mask(int x, int w)
+{
+	return static_cast<ptn_dots_t>((1u << w) - 1u) << (w - x);
+}
+
+void ptn_snap_quarter_8(int left, int top, int ptn_id, int quarter)
+{
+	int y;
+	unsigned int vram_offset = vram_offset_muldiv(left, top);
+	int q_y;
+	ptn_dots_t q_mask;
+	long q_x;
+	ptn_t *ptn = ptn_with_id(ptn_id);
+
+	q_y = ptn_quarter_y(quarter);
+	q_mask = (quarter & 1)
+		? dot_mask(PTN_QUARTER_W, PTN_QUARTER_W)
+		: dot_mask(            0, PTN_QUARTER_W);
+	q_x = ptn_quarter_x(quarter);
+
+	for(y = q_y; y < (q_y + PTN_QUARTER_H); y++) {
+		#define snap_quarter_plane(P, offset, w) \
+			ptn->planes.P[y] &= q_mask; \
+			ptn->planes.P[y] |= (VRAM_CHUNK(P, offset, w) << q_x) & ~q_mask;
+
+		#define snap_quarter(offset, w) \
+			snap_quarter_plane(B, offset, w); \
+			snap_quarter_plane(R, offset, w); \
+			snap_quarter_plane(G, offset, w); \
+			snap_quarter_plane(E, offset, w);
+
+		snap_quarter(vram_offset, PTN_W);
+
+		#undef snap_quarter
+		#undef snap_quarter_plane
+		vram_offset += ROW_SIZE;
+	}
+}
+
+}
diff --git a/th01/main_07.cpp b/th01/main_07.cpp
new file mode 100644
index 00000000..f0eeec64
--- /dev/null
+++ b/th01/main_07.cpp
@@ -0,0 +1,10 @@
+/* ReC98
+ * -----
+ * Code segment #7 of TH01's REIIDEN.EXE
+ */
+
+#pragma option -Z
+
+#include "ReC98.h"
+
+#include "th01/formats/ptn_snap.cpp"
diff --git a/th01/op_07.cpp b/th01/op_07.cpp
new file mode 100644
index 00000000..a94fe78c
--- /dev/null
+++ b/th01/op_07.cpp
@@ -0,0 +1,10 @@
+/* ReC98
+ * -----
+ * Code segment #7 of TH01's OP.EXE
+ */
+
+#pragma option -Z
+
+#include "ReC98.h"
+
+#include "th01/formats/ptn_snap.cpp"
diff --git a/th01_op.asm b/th01_op.asm
index 7382fdf5..0b8de1cf 100644
--- a/th01_op.asm
+++ b/th01_op.asm
@@ -2285,235 +2285,6 @@ loc_D3B6:
 		leave
 		retf
 _egc_copy_rect_1_to_0	endp
-
-; ---------------------------------------------------------------------------
-		enter	4, 0
-		push	si
-		push	di
-		mov	di, [bp+0Ah]
-		mov	ax, [bp+8]
-		imul	ax, 50h
-		push	ax
-		mov	ax, [bp+6]
-		mov	bx, 8
-		cwd
-		idiv	bx
-		pop	dx
-		add	dx, ax
-		mov	si, dx
-		mov	ax, di
-		mov	bx, 40h
-		cwd
-		idiv	bx
-		shl	ax, 2
-		mov	bx, ax
-		mov	ax, word ptr (_ptn_images + 2)[bx]
-		mov	dx, word ptr _ptn_images[bx]
-		push	ax
-		mov	ax, di
-		mov	bx, 40h
-		push	dx
-		cwd
-		idiv	bx
-		imul	dx, size ptn_t
-		pop	ax
-		add	ax, dx
-		pop	dx
-		mov	[bp-2],	dx
-		mov	[bp-4],	ax
-		xor	cx, cx
-		jmp	short loc_D481
-; ---------------------------------------------------------------------------
-
-loc_D416:
-		les	bx, _VRAM_PLANE_B
-		add	bx, si
-		mov	eax, es:[bx]
-		mov	dx, cx
-		shl	dx, 2
-		les	bx, [bp-4]
-		add	bx, dx
-		mov	es:[bx+ptn_t.planes.PTN_B], eax
-		les	bx, _VRAM_PLANE_R
-		add	bx, si
-		mov	eax, es:[bx]
-		mov	dx, cx
-		shl	dx, 2
-		les	bx, [bp-4]
-		add	bx, dx
-		mov	es:[bx+ptn_t.planes.PTN_R], eax
-		les	bx, _VRAM_PLANE_G
-		add	bx, si
-		mov	eax, es:[bx]
-		mov	dx, cx
-		shl	dx, 2
-		les	bx, [bp-4]
-		add	bx, dx
-		mov	es:[bx+ptn_t.planes.PTN_G], eax
-		les	bx, _VRAM_PLANE_E
-		add	bx, si
-		mov	eax, es:[bx]
-		mov	dx, cx
-		shl	dx, 2
-		les	bx, [bp-4]
-		add	bx, dx
-		mov	es:[bx+ptn_t.planes.PTN_E], eax
-		add	si, ROW_SIZE
-		inc	cx
-
-loc_D481:
-		cmp	cx, PTN_H
-		jl	short loc_D416
-		pop	di
-		pop	si
-		leave
-		retf
-; ---------------------------------------------------------------------------
-		enter	0Eh, 0
-		push	si
-		push	di
-		mov	ax, [bp+8]
-		imul	ax, 50h
-		push	ax
-		mov	ax, [bp+6]
-		mov	bx, 8
-		cwd
-		idiv	bx
-		pop	dx
-		add	dx, ax
-		mov	di, dx
-		mov	ax, [bp+0Ah]
-		mov	bx, 40h
-		cwd
-		idiv	bx
-		shl	ax, 2
-		mov	bx, ax
-		mov	ax, word ptr (_ptn_images + 2)[bx]
-		mov	dx, word ptr _ptn_images[bx]
-		push	ax
-		mov	ax, [bp+0Ah]
-		mov	bx, 40h
-		push	dx
-		cwd
-		idiv	bx
-		imul	dx, size ptn_t
-		pop	ax
-		add	ax, dx
-		pop	dx
-		mov	[bp-0Ch], dx
-		mov	[bp-0Eh], ax
-		test	byte ptr [bp+0Ch], 2
-		jz	short loc_D4DF
-		mov	ax, 10h
-		jmp	short loc_D4E1
-; ---------------------------------------------------------------------------
-
-loc_D4DF:
-		xor	ax, ax
-
-loc_D4E1:
-		mov	[bp-2],	ax
-		test	byte ptr [bp+0Ch], 1
-		jz	short loc_D4F2
-		mov	eax, 0FFFFh
-		jmp	short loc_D4F8
-; ---------------------------------------------------------------------------
-
-loc_D4F2:
-		mov	eax, 0FFFF0000h
-
-loc_D4F8:
-		mov	[bp-6],	eax
-		test	byte ptr [bp+0Ch], 1
-		jz	short loc_D507
-		mov	ax, 10h
-		jmp	short loc_D509
-; ---------------------------------------------------------------------------
-
-loc_D507:
-		xor	ax, ax
-
-loc_D509:
-		cwde
-		mov	[bp-0Ah], eax
-		mov	si, [bp-2]
-		jmp	loc_D5E8
-; ---------------------------------------------------------------------------
-
-loc_D515:
-		mov	ax, si
-		shl	ax, 2
-		les	bx, [bp-0Eh]
-		add	bx, ax
-		mov	eax, [bp-6]
-		and	es:[bx+ptn_t.planes.PTN_B], eax
-		les	bx, _VRAM_PLANE_B
-		add	bx, di
-		mov	eax, es:[bx]
-		mov	cl, [bp-0Ah]
-		shl	eax, cl
-		mov	edx, [bp-6]
-		not	edx
-		and	eax, edx
-		mov	dx, si
-		shl	dx, 2
-		les	bx, [bp-0Eh]
-		add	bx, dx
-		or	es:[bx+ptn_t.planes.PTN_B], eax
-		mov	eax, [bp-6]
-		and	es:[bx+ptn_t.planes.PTN_R], eax
-		les	bx, _VRAM_PLANE_R
-		add	bx, di
-		mov	eax, es:[bx]
-		shl	eax, cl
-		mov	edx, [bp-6]
-		not	edx
-		and	eax, edx
-		mov	dx, si
-		shl	dx, 2
-		les	bx, [bp-0Eh]
-		add	bx, dx
-		or	es:[bx+ptn_t.planes.PTN_R], eax
-		mov	eax, [bp-6]
-		and	es:[bx+ptn_t.planes.PTN_G], eax
-		les	bx, _VRAM_PLANE_G
-		add	bx, di
-		mov	eax, es:[bx]
-		shl	eax, cl
-		mov	edx, [bp-6]
-		not	edx
-		and	eax, edx
-		mov	dx, si
-		shl	dx, 2
-		les	bx, [bp-0Eh]
-		add	bx, dx
-		or	es:[bx+ptn_t.planes.PTN_G], eax
-		mov	eax, [bp-6]
-		and	es:[bx+ptn_t.planes.PTN_E], eax
-		les	bx, _VRAM_PLANE_E
-		add	bx, di
-		mov	eax, es:[bx]
-		shl	eax, cl
-		mov	edx, [bp-6]
-		not	edx
-		and	eax, edx
-		mov	dx, si
-		shl	dx, 2
-		les	bx, [bp-0Eh]
-		add	bx, dx
-		or	es:[bx+ptn_t.planes.PTN_E], eax
-		add	di, ROW_SIZE
-		inc	si
-
-loc_D5E8:
-		mov	ax, [bp-2]
-		add	ax, 10h
-		cmp	ax, si
-		jg	loc_D515
-		pop	di
-		pop	si
-		leave
-		retf
 op_07_TEXT	ends
 
 ; ===========================================================================
diff --git a/th01_reiiden.asm b/th01_reiiden.asm
index 4ba84a10..b96e6e0e 100644
--- a/th01_reiiden.asm
+++ b/th01_reiiden.asm
@@ -5460,264 +5460,8 @@ loc_104B1:
 		retf
 _egc_copy_rect_1_to_0	endp
 
-
-; =============== S U B	R O U T	I N E =======================================
-
-; Attributes: bp-based frame
-
-sub_104C2	proc far
-
-@@ptn		= dword	ptr -4
-arg_0		= word ptr  6
-arg_2		= word ptr  8
-arg_4		= word ptr  0Ah
-
-		enter	4, 0
-		push	si
-		push	di
-		mov	di, [bp+arg_4]
-		mov	ax, [bp+arg_2]
-		imul	ax, 50h
-		push	ax
-		mov	ax, [bp+arg_0]
-		mov	bx, 8
-		cwd
-		idiv	bx
-		pop	dx
-		add	dx, ax
-		mov	si, dx
-		mov	ax, di
-		mov	bx, 40h
-		cwd
-		idiv	bx
-		shl	ax, 2
-		mov	bx, ax
-		mov	ax, word ptr (_ptn_images + 2)[bx]
-		mov	dx, word ptr _ptn_images[bx]
-		push	ax
-		mov	ax, di
-		mov	bx, 40h
-		push	dx
-		cwd
-		idiv	bx
-		imul	dx, size ptn_t
-		pop	ax
-		add	ax, dx
-		pop	dx
-		mov	word ptr [bp+@@ptn+2], dx
-		mov	word ptr [bp+@@ptn], ax
-		xor	cx, cx
-		jmp	short loc_1057C
-; ---------------------------------------------------------------------------
-
-loc_10511:
-		les	bx, _VRAM_PLANE_B
-		add	bx, si
-		mov	eax, es:[bx]
-		mov	dx, cx
-		shl	dx, 2
-		les	bx, [bp+@@ptn]
-		add	bx, dx
-		mov	es:[bx+ptn_t.planes.PTN_B], eax
-		les	bx, _VRAM_PLANE_R
-		add	bx, si
-		mov	eax, es:[bx]
-		mov	dx, cx
-		shl	dx, 2
-		les	bx, [bp+@@ptn]
-		add	bx, dx
-		mov	es:[bx+ptn_t.planes.PTN_R], eax
-		les	bx, _VRAM_PLANE_G
-		add	bx, si
-		mov	eax, es:[bx]
-		mov	dx, cx
-		shl	dx, 2
-		les	bx, [bp+@@ptn]
-		add	bx, dx
-		mov	es:[bx+ptn_t.planes.PTN_G], eax
-		les	bx, _VRAM_PLANE_E
-		add	bx, si
-		mov	eax, es:[bx]
-		mov	dx, cx
-		shl	dx, 2
-		les	bx, [bp+@@ptn]
-		add	bx, dx
-		mov	es:[bx+ptn_t.planes.PTN_E], eax
-		add	si, ROW_SIZE
-		inc	cx
-
-loc_1057C:
-		cmp	cx, PTN_H
-		jl	short loc_10511
-		pop	di
-		pop	si
-		leave
-		retf
-sub_104C2	endp
-
-
-; =============== S U B	R O U T	I N E =======================================
-
-; Attributes: bp-based frame
-
-sub_10585	proc far
-
-@@ptn		= dword	ptr -0Eh
-var_A		= dword	ptr -0Ah
-var_6		= dword	ptr -6
-var_2		= word ptr -2
-arg_0		= word ptr  6
-arg_2		= word ptr  8
-arg_4		= word ptr  0Ah
-arg_6		= byte ptr  0Ch
-
-		enter	0Eh, 0
-		push	si
-		push	di
-		mov	ax, [bp+arg_2]
-		imul	ax, 50h
-		push	ax
-		mov	ax, [bp+arg_0]
-		mov	bx, 8
-		cwd
-		idiv	bx
-		pop	dx
-		add	dx, ax
-		mov	di, dx
-		mov	ax, [bp+arg_4]
-		mov	bx, 40h
-		cwd
-		idiv	bx
-		shl	ax, 2
-		mov	bx, ax
-		mov	ax, word ptr (_ptn_images + 2)[bx]
-		mov	dx, word ptr _ptn_images[bx]
-		push	ax
-		mov	ax, [bp+arg_4]
-		mov	bx, 40h
-		push	dx
-		cwd
-		idiv	bx
-		imul	dx, size ptn_t
-		pop	ax
-		add	ax, dx
-		pop	dx
-		mov	word ptr [bp+@@ptn+2], dx
-		mov	word ptr [bp+@@ptn], ax
-		test	[bp+arg_6], 2
-		jz	short loc_105DA
-		mov	ax, 10h
-		jmp	short loc_105DC
-; ---------------------------------------------------------------------------
-
-loc_105DA:
-		xor	ax, ax
-
-loc_105DC:
-		mov	[bp+var_2], ax
-		test	[bp+arg_6], 1
-		jz	short loc_105ED
-		mov	eax, 0FFFFh
-		jmp	short loc_105F3
-; ---------------------------------------------------------------------------
-
-loc_105ED:
-		mov	eax, 0FFFF0000h
-
-loc_105F3:
-		mov	[bp+var_6], eax
-		test	[bp+arg_6], 1
-		jz	short loc_10602
-		mov	ax, 10h
-		jmp	short loc_10604
-; ---------------------------------------------------------------------------
-
-loc_10602:
-		xor	ax, ax
-
-loc_10604:
-		cwde
-		mov	[bp+var_A], eax
-		mov	si, [bp+var_2]
-		jmp	loc_106E3
-; ---------------------------------------------------------------------------
-
-loc_10610:
-		mov	ax, si
-		shl	ax, 2
-		les	bx, [bp+@@ptn]
-		add	bx, ax
-		mov	eax, [bp+var_6]
-		and	es:[bx+ptn_t.planes.PTN_B], eax
-		les	bx, _VRAM_PLANE_B
-		add	bx, di
-		mov	eax, es:[bx]
-		mov	cl, byte ptr [bp+var_A]
-		shl	eax, cl
-		mov	edx, [bp+var_6]
-		not	edx
-		and	eax, edx
-		mov	dx, si
-		shl	dx, 2
-		les	bx, [bp+@@ptn]
-		add	bx, dx
-		or	es:[bx+ptn_t.planes.PTN_B], eax
-		mov	eax, [bp+var_6]
-		and	es:[bx+ptn_t.planes.PTN_R], eax
-		les	bx, _VRAM_PLANE_R
-		add	bx, di
-		mov	eax, es:[bx]
-		shl	eax, cl
-		mov	edx, [bp+var_6]
-		not	edx
-		and	eax, edx
-		mov	dx, si
-		shl	dx, 2
-		les	bx, [bp+@@ptn]
-		add	bx, dx
-		or	es:[bx+ptn_t.planes.PTN_R], eax
-		mov	eax, [bp+var_6]
-		and	es:[bx+ptn_t.planes.PTN_G], eax
-		les	bx, _VRAM_PLANE_G
-		add	bx, di
-		mov	eax, es:[bx]
-		shl	eax, cl
-		mov	edx, [bp+var_6]
-		not	edx
-		and	eax, edx
-		mov	dx, si
-		shl	dx, 2
-		les	bx, [bp+@@ptn]
-		add	bx, dx
-		or	es:[bx+ptn_t.planes.PTN_G], eax
-		mov	eax, [bp+var_6]
-		and	es:[bx+ptn_t.planes.PTN_E], eax
-		les	bx, _VRAM_PLANE_E
-		add	bx, di
-		mov	eax, es:[bx]
-		shl	eax, cl
-		mov	edx, [bp+var_6]
-		not	edx
-		and	eax, edx
-		mov	dx, si
-		shl	dx, 2
-		les	bx, [bp+@@ptn]
-		add	bx, dx
-		or	es:[bx+ptn_t.planes.PTN_E], eax
-		add	di, ROW_SIZE
-		inc	si
-
-loc_106E3:
-		mov	ax, [bp+var_2]
-		add	ax, 10h
-		cmp	ax, si
-		jg	loc_10610
-		pop	di
-		pop	si
-		leave
-		retf
-sub_10585	endp
-
+	extern _ptn_snap_8:proc
+	extern _ptn_snap_quarter_8:proc
 main_07_TEXT	ends
 
 ; ===========================================================================
@@ -18762,14 +18506,14 @@ loc_18A3A:
 		mov	ax, si
 		cwd
 		idiv	bx
-		add	ax, 146h
+		add	ax, (PTN_SLOT_5 + 6)
 		push	ax
-		push	10h
+		push	16
 		mov	ax, si
 		shl	ax, 4
-		add	ax, 100h
+		add	ax, 256
 		push	ax
-		call	sub_10585
+		call	_ptn_snap_quarter_8
 		add	sp, 8
 		inc	si
 
@@ -18795,12 +18539,12 @@ loc_18A60:
 
 loc_18A96:
 		push	si
-		push	1480010h
+		push	((PTN_SLOT_5 + 8) shl 16) or 16
 		mov	ax, si
 		shl	ax, 4
-		add	ax, 190h
+		add	ax, 400
 		push	ax
-		call	sub_10585
+		call	_ptn_snap_quarter_8
 		add	sp, 8
 		inc	si
 
@@ -18859,14 +18603,14 @@ loc_18B0D:
 		mov	ax, si
 		cwd
 		idiv	bx
-		add	ax, 14Ah
+		add	ax, (PTN_SLOT_5 + 10)
 		push	ax
 		push	0
 		mov	ax, si
 		shl	ax, 4
-		add	ax, 100h
+		add	ax, 256
 		push	ax
-		call	sub_10585
+		call	_ptn_snap_quarter_8
 		add	sp, 8
 		inc	si
 
@@ -18893,12 +18637,12 @@ loc_18B33:
 
 loc_18B6D:
 		push	si
-		push	14C0000h
+		push	((PTN_SLOT_5 + 12) shl 16) or 0
 		mov	ax, si
 		shl	ax, 4
-		add	ax, 190h
+		add	ax, 400
 		push	ax
-		call	sub_10585
+		call	_ptn_snap_quarter_8
 		add	sp, 8
 		inc	si
 
@@ -19206,7 +18950,7 @@ loc_18DA0:
 		mov	ax, si
 		cwd
 		idiv	bx
-		add	ax, 140h
+		add	ax, PTN_SLOT_5
 		push	ax
 		mov	ax, si
 		mov	bx, 6
@@ -19218,9 +18962,9 @@ loc_18DA0:
 		cwd
 		idiv	bx
 		shl	dx, 4
-		add	dx, 80h
+		add	dx, 128
 		push	dx
-		call	sub_10585
+		call	_ptn_snap_quarter_8
 		add	sp, 8
 		pushd	0
 		mov	ax, si
@@ -19352,7 +19096,7 @@ loc_18EB3:
 		mov	ax, si
 		cwd
 		idiv	bx
-		add	ax, 140h
+		add	ax, PTN_SLOT_5
 		push	ax
 		mov	ax, si
 		mov	bx, 6
@@ -19364,9 +19108,9 @@ loc_18EB3:
 		cwd
 		idiv	bx
 		shl	dx, 4
-		add	dx, 80h
+		add	dx, 128
 		push	dx
-		call	sub_10585
+		call	_ptn_snap_quarter_8
 		add	sp, 8
 		push	0
 		call	_graph_accesspage_func
@@ -19427,14 +19171,14 @@ loc_18F39:
 		mov	ax, si
 		cwd
 		idiv	bx
-		add	ax, 144h
+		add	ax, (PTN_SLOT_5 + 4)
 		push	ax
-		push	10h
+		push	16
 		mov	ax, si
 		shl	ax, 4
-		add	ax, 80h
+		add	ax, 128
 		push	ax
-		call	sub_10585
+		call	_ptn_snap_quarter_8
 		add	sp, 8
 		push	10000h
 		push	10h
@@ -19554,14 +19298,14 @@ loc_1901D:
 		mov	ax, si
 		cwd
 		idiv	bx
-		add	ax, 144h
+		add	ax, (PTN_SLOT_5 + 4)
 		push	ax
-		push	10h
+		push	16
 		mov	ax, si
 		shl	ax, 4
-		add	ax, 80h
+		add	ax, 128
 		push	ax
-		call	sub_10585
+		call	_ptn_snap_quarter_8
 		add	sp, 8
 		push	0
 		call	_graph_accesspage_func
@@ -19606,10 +19350,7 @@ sub_19085	proc far
 var_4		= byte ptr -4
 
 		enter	4, 0
-		pushd	142h
-		push	200260h
-		call	sub_10585
-		add	sp, 8
+		call	_ptn_snap_quarter_8 c, large (32 shl 16) or 608, large (PTN_SLOT_5 + 2)
 		push	ss
 		lea	ax, [bp+var_4]
 		push	ax
@@ -19823,11 +19564,7 @@ var_6		= byte ptr -6
 ; ---------------------------------------------------------------------------
 
 loc_19274:
-		push	si
-		push	14D0000h
-		push	200h
-		call	sub_10585
-		add	sp, 8
+		call	_ptn_snap_quarter_8 c, 512, large ((PTN_SLOT_5 + 13) shl 16) or 0, si
 		inc	si
 
 loc_19287:
diff --git a/th01_reiiden_2.inc b/th01_reiiden_2.inc
index 4cabfee2..f63f4e38 100644
--- a/th01_reiiden_2.inc
+++ b/th01_reiiden_2.inc
@@ -5229,7 +5229,7 @@ sub_1E4EC	endp
 
 sub_1E526	proc far
 
-var_6		= word ptr -6
+@@image		= word ptr -6
 var_4		= word ptr -4
 var_2		= word ptr -2
 
@@ -5240,7 +5240,7 @@ var_2		= word ptr -2
 		mov	[bp+var_2], ax
 		mov	ax, point_3982A.y
 		mov	[bp+var_4], ax
-		mov	[bp+var_6], 3
+		mov	[bp+@@image], 3
 		push	1
 		call	_graph_accesspage_func
 		pop	cx
@@ -5254,8 +5254,8 @@ loc_1E549:
 ; ---------------------------------------------------------------------------
 
 loc_1E54D:
-		mov	ax, [bp+var_6]
-		add	ax, 80h	; '?'
+		mov	ax, [bp+@@image]
+		add	ax, PTN_SLOT_2
 		push	ax
 		mov	ax, di
 		shl	ax, 5
@@ -5265,9 +5265,9 @@ loc_1E54D:
 		shl	ax, 5
 		add	ax, [bp+var_2]
 		push	ax
-		call	sub_104C2
+		call	_ptn_snap_8
 		add	sp, 6
-		inc	[bp+var_6]
+		inc	[bp+@@image]
 		inc	si
 
 loc_1E572:
@@ -11502,14 +11502,14 @@ loc_219DD:
 		mov	ax, [bp+var_2]
 		cwd
 		idiv	bx
-		add	ax, 14Eh
+		add	ax, (PTN_SLOT_5 + 14)
 		push	ax
-		push	30h ; '0'
+		push	48
 		mov	ax, [bp+var_2]
 		shl	ax, 4
-		add	ax, 80h	; '?'
+		add	ax, 128
 		push	ax
-		call	sub_10585
+		call	_ptn_snap_quarter_8
 		add	sp, 8
 		mov	ax, [bp+var_2]
 		cmp	ax, word_3A1E7
@@ -11550,14 +11550,14 @@ loc_21A35:
 		mov	ax, di
 		cwd
 		idiv	bx
-		add	ax, 14Eh
+		add	ax, (PTN_SLOT_5 + 14)
 		push	ax
-		push	30h ; '0'
+		push	48
 		mov	ax, di
 		shl	ax, 4
-		add	ax, 80h	; '?'
+		add	ax, 128
 		push	ax
-		call	sub_10585
+		call	_ptn_snap_quarter_8
 		add	sp, 8
 		cmp	di, word_3A1E7
 		jnb	short loc_21A64
@@ -17656,7 +17656,7 @@ sub_24E33	proc far
 
 var_A		= word ptr -0Ah
 var_8		= word ptr -8
-var_6		= word ptr -6
+@@image		= word ptr -6
 var_4		= word ptr -4
 var_2		= word ptr -2
 arg_0		= word ptr  6
@@ -17690,7 +17690,7 @@ loc_24E6E:
 		mov	[bp+var_4], ax
 
 loc_24E71:
-		mov	[bp+var_6], 0
+		mov	[bp+@@image], 0
 		push	1
 		call	_graph_accesspage_func
 		pop	cx
@@ -17704,8 +17704,8 @@ loc_24E82:
 ; ---------------------------------------------------------------------------
 
 loc_24E86:
-		mov	ax, [bp+var_6]
-		add	ax, 80h	; '?'
+		mov	ax, [bp+@@image]
+		add	ax, PTN_SLOT_2
 		push	ax
 		mov	ax, di
 		shl	ax, 5
@@ -17715,9 +17715,9 @@ loc_24E86:
 		shl	ax, 5
 		add	ax, [bp+var_2]
 		push	ax
-		call	sub_104C2
+		call	_ptn_snap_8
 		add	sp, 6
-		inc	[bp+var_6]
+		inc	[bp+@@image]
 		inc	si
 
 loc_24EAB:
@@ -23858,7 +23858,7 @@ sub_287D9	endp
 
 sub_28852	proc near
 
-var_6		= word ptr -6
+@@image		= word ptr -6
 var_4		= word ptr -4
 var_2		= word ptr -2
 
@@ -23869,7 +23869,7 @@ var_2		= word ptr -2
 		mov	[bp+var_2], ax
 		mov	ax, word_39A2B
 		mov	[bp+var_4], ax
-		mov	[bp+var_6], 0
+		mov	[bp+@@image], 0
 		push	1
 		call	_graph_accesspage_func
 		pop	cx
@@ -23883,8 +23883,8 @@ loc_28875:
 ; ---------------------------------------------------------------------------
 
 loc_28879:
-		mov	ax, [bp+var_6]
-		add	ax, 80h	; '?'
+		mov	ax, [bp+@@image]
+		add	ax, PTN_SLOT_2
 		push	ax
 		mov	ax, di
 		shl	ax, 5
@@ -23894,9 +23894,9 @@ loc_28879:
 		shl	ax, 5
 		add	ax, [bp+var_2]
 		push	ax
-		call	sub_104C2
+		call	_ptn_snap_8
 		add	sp, 6
-		inc	[bp+var_6]
+		inc	[bp+@@image]
 		inc	si
 
 loc_2889E: