井桁 ・ いげた ・ igeta | 井筒 ・ いづつ ・ izutsu ・ idzutsu
The shape of a well's edge made of crossed beams as viewed from above. Hashmark (#). A design consisting of two pairs of crossed lines. A cross or square formed with four slightly overlapping lines. The design is used as a basic kasuri pattern in woven fabrics. The shape can also be rotated (sometimes slightly compressed) so it forms a diamond.
Izutsu is also used to refer to the same shape (it is the top part of a well often made with beams).