Purple air erasable marker which will help you to transfer a weaving pattern from paper to warp.
The drawing disappears when exposed to moist in the air. After few hours it will disappear automatically, but you can also remove it faster using ex. the iron steam.
The marker works best for more complicated patterns, wall hangings, tapestries or kilims. You can use it to transfer a pattern to the warp.
Erasable marker is a great solution for handstitching and patchwork too.