Scott Kim created the original ambigram (he also calls them inversions) that is featured in this animation for a family holiday card in 1985. To create the angular letters, he cut the letter shapes out of construction paper and then traced them into his computer. The text reads the same whether it is viewed normally or rotated 180 degrees.
More of Scott Kim’s ambigrams and other puzzles can be found on his website at www.scottkim.com.