How to tie a knot
D. Indumathi, The Institute of Mathematical Sciences, Chennai

Starting from shoes to torn bags, you must have tied knots several times. Here are some illustrations on how to tie different kinds of knots and where they come in use.
1. Square knot: Also called a reef knot, it is used to to tie up bundles. It closely resembles the granny knot; both are used for typing up bundles and shoe-laces but are not good for heavy objects.
2. Clove hitch: A hitch is used to tie something to a support, like a tree. It is quick and easy, but an additional knot to prevent it from slipping open may be required.
3. Bowline: It is the most important knot to use when you are climbing down a wall or rocks. It makes a loop at one end of the rope that doesn't slide open or closed when pulled, so it keeps it shape.
4. Sheet bend: A bend is when one rope is connected to another. A sheet bend is useful when you have to join ropes of different sizes.
5. Carrick bend: This is like a square knot to tie to ropes together, but it is easier to undo.
6. Half hitch: Two half-hitches are used to tie a line to a tree or pole (for hanging up washed clothes) or while pitching a tent.
7. Taut line hitch: If you want to make sure that the rope is taut (tight and doesn't sag), you can use the taut line hitch where the knots slide along the line but don't come off as long as there is tension on the "taut" side of the rope. (This is important: the two sides of the rope are not under the same tension and the side that slides must be the long end of the rope).
8. Rolling hitch: Some times you may want to add a join to the middle of a line. You can use the rolling hitch which is similar to the taut line hitch.
9. Man harness: This is useful in making a knot when neither end of the rope is free. The object to be held is kept inside the loop that is made in the middle of the rope. Once the object is removed the knot slides off.
10. Trucker's hitch: Have you seen a mountain of goods tightly tied up on the back of a truck? If you need to pull a rope really tight around some goods, then the trucker's hitch is the knot of choice.
Images and text adapted from https://www.popsci.com/20-essential-knots-you-need-to-know/