3D printing with a desktop 3D printer requires some knowledge about printing supports for overhangs, arches and bridges.
You can download the file for 3D printing at https://www.thingiverse.com/thing:2871886
As an example of this, the letters H, T, and Y are used. Supports can hold up the overhangs for the letter T. The overhang in H may bridge unsupported, and the Y may print without support. The tail has to be supported because it does not touch the build plate, and the overhang of the arch should be supported.
You can also 3D print this at different orientations to demonstrate how orientation affects the quality of the print.
This is a small print, and you can also show students how to change colors in the print by using markers or changing filament colors as you 3D print.