Moving walls had to be avoided. However, some walls could be broken. Sand traps could be blown away, and fire could be blown out for a short time. Blocks could be moved to open passages or block spike pits. Blades could be used to split the bead into two, allowing the water to enter narrow passages. Green switches opened up passages which came in two types: large and small. The larger switch was activated by the bead, while the smaller switches could only be activated by the smaller split beads. Often two small switches had to be activated at the same time by both small beads. Another type of switch linked two ciphers and would activate traps on another cipher.