Grandpa R. obligingly cut some scrap 2x4 lumber into 2 each of the following sizes: 6", 5-1/2" and 4-1/2". Daughter and I then painted the back and sides of each block with black acrylic paint.
When dry, the fronts were then painted in lavender, cream and soft blue.
We used my Cricut™ machine to cut black vinyl letters with the Don Juan™ cartridge. We had to adjust the letter m a bit to fit with width of the block, but as you can see, it turned out really well.
Here is the original idea we saw on Pinterest, and modified/ simplified it for our blocks. If you'd like to see other ideas from Pinterest, type "family blocks" into the search bar.
Blessings ~ Juju