Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:3419351.

My kids kept breaking the original 5-way, so this one has a tiny bit of extra support on the middle joints. https://www.tinkercad.com/things/7dXLcn51Gjq-pvc-5-way

There is also a modified version of the sheet clip that can plug onto a pipe. https://www.tinkercad.com/things/b4y0bZvspP5-pvc-side-clip

The 4-way roof topper can connect 4 2-foot pipes together so that it can rest on top of a 2-foot by 2-foot square. https://www.tinkercad.com/things/covRruqC6m8-pvc-fort-roof-topper