Weaving with rattan core (also known as reed) is one of the more popular techniques being practiced, because it is easily available.[1] It is pliable, and when woven correctly, it is very sturdy. Also, while traditional materials like oak, hickory, and willow might be hard to come by, reed is plentiful and can be cut into any size or shape that might be needed for a pattern. This includes flat reed, which is used for most square baskets; oval reed, which is used for many round baskets; and round reed, which is used to twine; another advantage is that reed can also be dyed easily to look like oak or hickory. The type of baskets that reed is used for are most often referred to as "wicker" baskets, though another popular type of weaving known as "twining" is also a technique used in most wicker baskets. Wicker baskets are often used to store beer, grain, and even in some human sacrificing tribes, the heads of the sacrifice.[citation needed]