VIDEO HERE: https://youtu.be/LEe7jQBOjzI
A floppy 1x4x4, following along my floppy 1x5x5.
It is identical in size and shape to the 1x5x5. It's mechanically identical as well, just with the middle layer hidden and appropriate bandaging applied.
This puzzle turns very well with a spritz of silicon lube. This puzzle needs four 10mm M3 screws to assemble.