diff --git a/includes/defines.h b/includes/defines.h
index b3b604ff9..9fba0fb2e 100644
--- a/includes/defines.h
+++ b/includes/defines.h
@@ -14,8 +14,6 @@
 
 #define SERVER "powdertoy.co.uk"
 
-#undef PLOSS
-
 #define THUMB_CACHE_SIZE 256
 
 #define IMGCONNS 3
@@ -45,11 +43,11 @@ extern unsigned char ZSIZE;
 #define ISTP    (CELL/2)
 #define CFDS	(4.0f/CELL)
 
-#define TSTEPP 0.3f
-#define TSTEPV 0.4f
-#define VADV 0.3f
-#define VLOSS 0.999f
-#define PLOSS 0.9999f
+#define AIR_TSTEPP 0.3f
+#define AIR_TSTEPV 0.4f
+#define AIR_VADV 0.3f
+#define AIR_VLOSS 0.999f
+#define AIR_PLOSS 0.9999f
 
 #define GRID_X 5
 #define GRID_Y 4
diff --git a/src/air.c b/src/air.c
index 33a491376..e9a8b9e93 100644
--- a/src/air.c
+++ b/src/air.c
@@ -86,8 +86,8 @@ void update_air(void)
 			dp = 0.0f;
 			dp += vx[y][x-1] - vx[y][x];
 			dp += vy[y-1][x] - vy[y][x];
-			pv[y][x] *= PLOSS;
-			pv[y][x] += dp*TSTEPP;
+			pv[y][x] *= AIR_PLOSS;
+			pv[y][x] += dp*AIR_TSTEPP;
 		}
 
 	for (y=0; y<YRES/CELL-1; y++)
@@ -96,10 +96,10 @@ void update_air(void)
 			dx = dy = 0.0f;
 			dx += pv[y][x] - pv[y][x+1];
 			dy += pv[y][x] - pv[y+1][x];
-			vx[y][x] *= VLOSS;
-			vy[y][x] *= VLOSS;
-			vx[y][x] += dx*TSTEPV;
-			vy[y][x] += dy*TSTEPV;
+			vx[y][x] *= AIR_VLOSS;
+			vy[y][x] *= AIR_VLOSS;
+			vx[y][x] += dx*AIR_TSTEPV;
+			vy[y][x] += dy*AIR_TSTEPV;
 			if (bmap[y][x]==WL_WALL || bmap[y][x+1]==WL_WALL ||
 			        bmap[y][x]==WL_WALLELEC || bmap[y][x+1]==WL_WALLELEC ||
 			        (bmap[y][x]==WL_EWALL && !emap[y][x]) ||
@@ -148,20 +148,20 @@ void update_air(void)
 			if (i>=2 && i<XRES/CELL-3 &&
 			        j>=2 && j<YRES/CELL-3)
 			{
-				dx *= 1.0f - VADV;
-				dy *= 1.0f - VADV;
+				dx *= 1.0f - AIR_VADV;
+				dy *= 1.0f - AIR_VADV;
 
-				dx += VADV*(1.0f-tx)*(1.0f-ty)*vx[j][i];
-				dy += VADV*(1.0f-tx)*(1.0f-ty)*vy[j][i];
+				dx += AIR_VADV*(1.0f-tx)*(1.0f-ty)*vx[j][i];
+				dy += AIR_VADV*(1.0f-tx)*(1.0f-ty)*vy[j][i];
 
-				dx += VADV*tx*(1.0f-ty)*vx[j][i+1];
-				dy += VADV*tx*(1.0f-ty)*vy[j][i+1];
+				dx += AIR_VADV*tx*(1.0f-ty)*vx[j][i+1];
+				dy += AIR_VADV*tx*(1.0f-ty)*vy[j][i+1];
 
-				dx += VADV*(1.0f-tx)*ty*vx[j+1][i];
-				dy += VADV*(1.0f-tx)*ty*vy[j+1][i];
+				dx += AIR_VADV*(1.0f-tx)*ty*vx[j+1][i];
+				dy += AIR_VADV*(1.0f-tx)*ty*vy[j+1][i];
 
-				dx += VADV*tx*ty*vx[j+1][i+1];
-				dy += VADV*tx*ty*vy[j+1][i+1];
+				dx += AIR_VADV*tx*ty*vx[j+1][i+1];
+				dy += AIR_VADV*tx*ty*vy[j+1][i+1];
 			}
 
 			if (bmap[y][x] == WL_FAN)
diff --git a/src/powder.c b/src/powder.c
index 493dec71f..f8a5d3d78 100644
--- a/src/powder.c
+++ b/src/powder.c
@@ -1113,7 +1113,7 @@ int nearest_part(int ci, int t)
 	{
 		if (parts[i].type==t&&!parts[i].life&&i!=ci)
 		{
-			ndistance = abs((cx-parts[i].x)+(cy-parts[i].y));// Faster but less accurate  Older: sqrt(pow(cx-parts[i].x, 2)+pow(cy-parts[i].y, 2));
+			ndistance = abs(cx-parts[i].x)+abs(cy-parts[i].y);// Faster but less accurate  Older: sqrt(pow(cx-parts[i].x, 2)+pow(cy-parts[i].y, 2));
 			if (ndistance<distance)
 			{
 				distance = ndistance;
@@ -1290,9 +1290,9 @@ void update_particles_i(pixel *vid, int start, int inc)
 	}
 	if (ISGOL==1&&++CGOL>=GSPEED)//GSPEED is frames per generation
 	{
+		int createdsomething = 0;
 		CGOL=0;
 		ISGOL=0;
-		int createdsomething = 0;
 		for (nx=CELL; nx<XRES-CELL; nx++)
 			for (ny=CELL; ny<YRES-CELL; ny++)
 			{
@@ -1553,7 +1553,7 @@ void update_particles_i(pixel *vid, int start, int inc)
 							else t = PT_DSTW;
 						}
 						else if (t==PT_LAVA) {
-							if (parts[i].ctype&&parts[i].ctype!=PT_LAVA) {
+							if (parts[i].ctype && parts[i].ctype<PT_NUM && parts[i].ctype!=PT_LAVA) {
 								if (ptransitions[parts[i].ctype].tht==PT_LAVA&&pt>=ptransitions[parts[i].ctype].thv) s = 0;
 								else if (parts[i].ctype==PT_THRM&&pt>=ptransitions[PT_BMTL].thv) s = 0;
 								else if (pt>=973.0f) s = 0; // freezing point for lava with any other (not listed in ptransitions as turning into lava) ctype