I purchased the little mechanical computer toy/game called "Turing Tumble" ( https://www.turingtumble.com ). It is a really cool toy, but the board for ours was warped enough so that the plastic pieces that connect the marble release to the flippers at the bottom were touching the pegs in certain places.

See these threads on the Turing Tumble Community web site for detailts:

https://community.turingtumble.com/t/connectors-touching-back-of-board-and-blocking-holes/623
https://community.turingtumble.com/t/bit-can-not-move-in-one-place/277

This Thing is a small piece that clips onto the connector and spaces it far enough out from the board so that the pegs do not impact it.

As always, I've included the Fusion 360 (CAD) source file in case you would like to make changes to the design.