Tacnode

Okay kiddo, let me explain what a tacnode is.

Imagine you have a piece of string and you tie one end of it to a pencil. Now, you hold onto the other end of the string with your other hand and start moving the pencil around. As you move the pencil, the string follows along and creates a curve on a piece of paper.

Now, let's say you keep moving the pencil around and eventually the string gets all tangled up. There is a point where the string crosses over itself and touches in more than one spot. This is called a tacnode.

A tacnode is a point on a line or curve where it looks like the line is touching itself or crossing over. It's like a little knot in the line.

Mathematicians like to study these types of points because they can tell us a lot about how the curve or line is behaving. They can also be important in things like computer graphics or designing machines that move along a curved path.

So, that's what a tacnode is, kiddo. It's like a little knot on a line or curve.