form of knots in rug

Basically there are two kind of knots are woven in rugs;

1-Persian knot (Seneh knot) which has twisted wrap threads and it is made by looping
the knot round two wrap-threads to produce finer and firmer knots which make the rug
last longer.The Persian rug have more knots than any other rugs which make the rug have higher price than any other rug this kind of knots are making in Iran and Afghanistan.The persian knot is made by passing the thread under one wrap-thread and then round over the next,so that a pile-end shows between every warp-thread.

2-Turkish knot is made by looping the knot round two wrap-threads and bringing the ends of yarn,the pile,out between them, this knots are making in Turkey and Caucasus.