After looking for magnetic letters that would hold up to my toddler and being disappointed by what I found, I designed my own.
Using Fusion 360 and the Roboto Mono font, I laid out the position for each magnet and created a void in the models so that strong neodymium magnets could be inserted mid-print.
The magnets are fully enclosed in the plastic, so it’s safe for a child to play with. They can be easily cleaned and won’t scratch the refrigerator or dishwasher surface when slid around.