HOW TO WEAVE KETUPAT CASING

Materials for weaving ketupat casings. The Ketupat is a savoury rice cake wrapped in woven coconut leaves. The stick which forms the spine of the leaves is removed with a paring knife so that the leaves are split in two ribbon-like pieces. The young leaves of the coconut plant are used. These young leaves are light yellow in colour with green edgings down the long outer sides of the leaves. The length of the coconut leaves is just right for ketupat weaving. The wider the leaves the bigger the ketupat casing will be. The instructions given below is for the traditional ketupat - somewhat square in shape. Another type of ketupat casing is woven in the shape of an onion - called ketupat bawang.
Pandan leaves may also be used. The pandan leaves used are of the long variety and not the type commonly used for food flavouring. However, because of the scent or flavour of the Pandan leaves, such leaves are not usually used when the ketupat is served as a complement to certain dishes as the pandan flavour might affect the taste of the accompanying dishes. Ketupat are therefore traditionally served plain without any flavour. However, some ketupat are boiled in coconut milk seasoned with some salt.
For decorative purposes, ketupat casings may be woven in multicoloured craft ribbons.

Some Weaving Tips
Briefly stated the ketupat weave comprises three vertical and three horizontal interlocking loops. The two ends of the split coconut leaves end up together at the diagonal opposite ends of the ketupat casing: the 2 narrow ends finish together diagonally opposite the two broad ends. The opening of the ketupat (into which rice is filled) is located at the top end where the broad ends of the leaves are located.
The leaves are initially handled iand placed in the manner illustrated in figure (1) below. When making the X, the B leaf should be longer than the A leaf so that there is sufficient space to line up the vertical loops.from the centre of cross to the B end of the leaf.
The 3 vertical loops (figures 2,3,4) are to be kept close together as otherwise it may be difficult to handle the weave when you get to stage (8) where the weave has to be turned around so that the bottom is turned up to face you. A loose weave may just fall apart then. Furthermore, you may also run out of the lengths of the leaves if the weave is woven too loose.

Source: http://web.singnet.com.sg/~hsh17/sect1ketupat.htm