diff --git a/graphics/gr/tunnel/t.bas b/graphics/gr/tunnel/t.bas
index 8c463f09..31b587da 100644
--- a/graphics/gr/tunnel/t.bas
+++ b/graphics/gr/tunnel/t.bas
@@ -1,12 +1,10 @@
 7 DIM A(9,9):FOR I=0 TO 8:FOR J=0 TO 8:A(I,J)=40/(2+I+J/7):NEXTJ,I
 10 GR:N=23
-15 FOR Q=0 TO 7
-20 T=19:FOR X=0 TO 7
-30 FOR I=T TO T-A(X,Q) STEP -1
+15 FOR Q=6 TO 0 STEP -1
+22 P=0
+25 FOR I=0 TO 19 STEP 1:IF 20-I<A(P,Q) THEN P=P+1
 40 Z=39-I:J=I+1:W=Z-1
-42 COLOR=N:HLIN J,W AT I:HLIN J,W AT Z:VLIN J,W AT I:VLIN J,W AT Z
-50 NEXT:T=T-A(X,Q):N=N-1
-60 NEXT:N=N+9:IF N=16 THEN N=32
-65 NEXT
+42 COLOR=N+P:HLIN J,W AT I:HLIN J,W AT Z:VLIN J,W AT I:VLIN J,W AT Z
+50 NEXT
+60 NEXT:N=N+1:IF N=32 THEN N=16
 70 GOTO 15
-