The big arms are attached to the egg thing with two magnets, so a kid shoving their hand into the moving parts is very safe; it just falls apart. And you can see the clever arrangement of the three moving parts (axis 1, axis 2, and lift/drop pen).
I have a Watercolorbot[1] which is like the world's most inexact plotter. But it's a lot of fun to watch it pick up paint on the brush and try to paint a gcode version of your design (also funny to see the patterns the slicer algo uses to try and fill blocks of color). Software was always a little fiddly, but still a fun idea.
The big arms are attached to the egg thing with two magnets, so a kid shoving their hand into the moving parts is very safe; it just falls apart. And you can see the clever arrangement of the three moving parts (axis 1, axis 2, and lift/drop pen).