I guess we all had that problem one time or another: You want to build something with catch blocks, but some things don't align properly because catch blocks are centered, and your day is ruined because the contraption you had been planning in your head all week is impossible. Some of these alignment problems could be solved with another catch block attached to the axis of the first one, but that would make things unnecessarily clangy. My simple idea: Adapters. They look very similar to catch blocks, with the only difference being that the central axis is rigid. This would be a good provisional solution until Keen has finally reworked cart building.