This is my take on the Tissue box contest. 

I thought I would do something unique and do a train, and it would be funny to have a tissue as the steam.

To put it together, you slide pieces in place starting with the FrontBase and FrontTrain, then add MiddleTrain, then BackBase. Add the tissue box inside the hole and close it off with the BackTrain. 

Also, add the Chute in the hole in the MiddleTrain.

most pieces are oriented to require no supports. FrontTrain will either need bridging settings turned on or support.

Material usage could definitely be optimized, since it could take around 1kg of plastic to print at full size (10000% in cura)