工字繋ぎ ・ こうじつなぎ ・ koujitsunagi
A repeating geometric pattern made up of interlocking kou (工) kanji. The design is often angled and slightly skewed. The endless repeating pattern is associated with longevity. Easily confused with the negative space in the similar sayagata pattern.
The name literally translates to linked-kou-characters.