diff --git a/plow/PlowTest.c b/plow/PlowTest.c
index 9be870c3..0e627e7c 100644
--- a/plow/PlowTest.c
+++ b/plow/PlowTest.c
@@ -143,6 +143,7 @@ PlowTest(w, cmd)
     Plane *plane;
     Edge edge;
     Tile *tp;
+    Tile *delay1 = NULL;
 
     if (!ToolGetEditBox(&editArea) || !ToolGetBox(&rootBoxDef, &rootBox))
 	return;
@@ -341,7 +342,7 @@ PlowTest(w, cmd)
 	    TiToRect(tp, &editArea);
 	    TiToRect(RT(tp), &area2);
 	    (void) GeoInclude(&area2, &editArea);
-	    plowMergeBottom(tp, plane);
+	    plowMergeBottom(&delay1, tp, plane);
 	    DBWAreaChanged(def, &editArea, DBW_ALLWINDOWS, &DBAllButSpaceBits);
 	    break;
 	case PC_MERGEUP:
@@ -350,7 +351,7 @@ PlowTest(w, cmd)
 	    TiToRect(tp, &editArea);
 	    TiToRect(RT(tp), &area2);
 	    (void) GeoInclude(&area2, &editArea);
-	    plowMergeTop(tp, plane);
+	    plowMergeTop(&delay1, tp, plane);
 	    DBWAreaChanged(def, &editArea, DBW_ALLWINDOWS, &DBAllButSpaceBits);
 	    break;
 	case PC_PRINT:
@@ -391,6 +392,7 @@ PlowTest(w, cmd)
 	    plowWhenBot = TRUE;
 	    break;
     }
+    TiFreeIf(delay1);
 }
 
 /*
diff --git a/plow/plow.h b/plow/plow.h
index b38c0f8d..b0fdefb1 100644
--- a/plow/plow.h
+++ b/plow/plow.h
@@ -22,6 +22,8 @@
 #define _MAGIC__PLOW__PLOW_H
 
 #include "utils/magic.h"
+#include "windows/windows.h"	/* MagWindow */
+#include "textio/txcommands.h"	/* TxCommand */
 
 /* Technology file clients */
 extern int PlowTechInit(), PlowTechFinal();
@@ -33,7 +35,7 @@ extern bool PlowDRCLine();
 extern bool Plow(CellDef *def, Rect *userRect, const TileTypeBitMask *layersp, int direction);
 
 /* Debugging command procedure */
-extern int PlowTest();
+extern void PlowTest(MagWindow *w, TxCommand *cmd);
 
 extern void PlowExtendJogHorizon();
 
diff --git a/plow/plowInt.h b/plow/plowInt.h
index a01c8548..6f1820e2 100644
--- a/plow/plowInt.h
+++ b/plow/plowInt.h
@@ -270,8 +270,8 @@ extern int  plowSrShadowInitial(int pNum, Rect *area, const TileTypeBitMask *okT
 extern bool plowYankMore();
 extern void PlowRandomTest();
 extern void plowDebugInit();
-extern void plowMergeBottom();
-extern void plowMergeTop();
+extern void plowMergeBottom(Tile **delay1, Tile *tp, Plane *plane); /* for PlowTest.c */
+extern void plowMergeTop(Tile **delay1, Tile *tp, Plane *plane); /* for PlowTest.c */
 extern void plowMoveEdge();
 extern int  plowShadowInitialRHS();
 extern int  plowShadowLHS();