This is a tertiary structural unit in some proteins where four beta strands form an antiparallel beta sheet. The design is similar to patterns found on Greek pottery. Although this motif has no specific function, it is found in many proteins. Frequently found in the shape of a beta barrel.

	 _______
	/	\
	|	|	N	C
	o	^	o	^
	o	o	o	o
	o	o	o	o
	o	o	o	o
	o	o	o	o
	o	o	o	o
	o	o	o	o
	V	o	V	o
	|	\_______/	|
	|			|
	\_______________________/

	N - amino terminus (start of motif)
	C - carboxy terminus (end of motif)