Need an easy knot to tie for an end loop? Look no further than the blood loop knot. The blood loop knot is often used for attaching a dropper when fishing deep water with several hooks. Diagram shows the following: Double the line back to make a loop of the size desired. Bring the end of the loop twice over the doubled part. Now pass the end of the loop through the first loop formed in the doubled part. Educational, instructional topological Knotology fun gifts for all who enjoy tying knots!