Hello
Probably already well known. File attached. Add a Shift register to a while loop and wiring the left SR node to a constant. The switching between replace SR with Tunnel, and vice versa leaves a black tunnel or an extra tunnel and a miswiring. Broken error arrow, but error dialog shows no error message. This eoor was first posted in the LAVA group, but my addition was to try switching back and forth and finding how this tunnel and miswiring multiplies.
Khan