1. Holy trefoils, math fans!
Knots
Holy trefoils, math fans!

2. The Inca & the Quipus
The Inca used quipus --colored strings with carefully placed knots-- to keep records of their trade with each other and with other tribes.
A quipus

3. Knots and Art
Celtic artwork uses knots.

4. Knots and Sailing Any good sailor can tie lots of different knots.
Bowline Knot (pronounced Boh-Lin)
Reef Knot
Angler’s Knot

5. What is a knot?
If you know how to tie a shoe, then you know what a knot is.
The only difference between this knot and a knot mathematically is that we connect the ends.

6. Are these knots the same? Or, are these knots different?
What do YOU think?
Knot 1
Knot 2

7. When are two knots the same?
Two knots are equivalent if you can deform one to the other without cutting the knot open.

8. Are these knots the same?
Can you use your rope to change one into the other?