diff -u -r angban~1/src/files.c angband/src/files.c
--- angban~1/src/files.c	Tue Jul 25 20:57:48 2000
+++ angband/src/files.c	Tue Sep  5 20:10:34 2000
@@ -1679,6 +1679,13 @@
 			/* Default */
 			c_put_str(TERM_SLATE, ".", row, col+n);
 
+			/* Hack -- Check immunities */
+			if ((x == 0) && (y < 4) &&
+			    (f[set] & ((TR2_IM_ACID) << y)))
+			{
+				c_put_str(TERM_WHITE, "*", row, col+n);
+			}
+
 			/* Check flags */
 			if (f[set] & flag) c_put_str(TERM_WHITE, "+", row, col+n);