clr=(red Shl 16)Or(green Shl 8)Or blue LockBuffer WritePixelFast spark\x,spark\y,clr WritePixelFast spark\x,spark\y+1,clr WritePixelFast spark\x+1,spark\y,clr WritePixelFast spark\x+1,spark\y+1,clr UnLockBuffer
should work.
clr=(red Shl 16)Or(green Shl 8)Or blue LockBuffer WritePixelFast spark\x,spark\y,clr WritePixelFast spark\x,spark\y+1,clr WritePixelFast spark\x+1,spark\y,clr WritePixelFast spark\x+1,spark\y+1,clr UnLockBuffer