A trap idea:
This trap can be used to close a Rock Barrier so that the player can't go back anymore.
Make a place where there are two Rock Barriers, the one that should be closed called R1, and the one that must be opened called R2. Place them like this:
ground
---------------
| | | |
R1> | | | | <R2
| | | |
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ground
Now, place a button linked to R1 and another one linked to R2 inside the upper and lower grounds, like this: (B1 linked to R1 and B2 linked to R2)
----
| B1 |
----
---------------
| | | |
R1> | | | | <R2
| | | |
---------------
----
| B2 |
----
B2's info (0) must be set to 1.
Finally, make a boulder on top of B1 and some crunch tiles of type 0 under the button.
Remember, the player must have the VBlade spell.
How it works:
When the player gets into this area, R1 is open. R2 is closed. The player must get to the middle of this area and use VBlade to open R2 (With the blade that flies down). But at the same time, the upper blade will hit the crunch tiles, breaking them, and the boulder will fall down in the hole (where the crunch tiles were) so that pressure will be released from B1, and R1 will be closed.
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Armadillopineapplemacintosh!