Nope, you just take down old koans to make new ones. Shirley Maclaine would be proud.
From the rules:
Breaking Down Old Koans
If, when building a new koan, the pieces you'd like to use are not available, tell everyone which pieces you're looking for. The Master must decide which koan or koans to break down, if any, taking into account the input of all of the Students as much as possible. If all of the Students agree to allow a certain koan to be broken down, the Master should always do so. To break down a koan, the Master returns the koan's marking stone and all its pieces to the box. If, when building a counter-example koan, the Master wants to use pieces that are not available, the Master will tell everyone which pieces are needed, and will decide which koan or koans to break down, taking into account the input of all of the Students as much as possible.
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