Refer to the grid below starting at point 1. The mouse will move through the remaining numbers on the grid in a clockwise direction. You should have a basic understanding of trigonometry to help identify when you are drawing a circle.

--------->-----1------>-------- | | | | | | | | | | | | | | -----8---------|---------2----- | | Q4 | | | Q1 | | ^ | | | | | V ---------------|--------------- | | | | | | | | | | | | | | 7______________|______________3 | | | | | | | | | | | | | | ---------------|--------------- ^ | Q3 | | | Q2 | V | | | | | | | -----6---------|---------4----- | | | | | | | | | | | | | | ---------<-----5-----<---------

**Which direction are we going?**

Below is a state table for determing clockwise direction, take the differences of the current mouse x and y values and the previous x and y values. The Q1 difference should result in a positive X value and a negative Y value, and so on. Keep a history of the direction to know if the mouse continues to move in a clokwise direction.

Quadrant CW Dir Rslt ----------------------- Q1 +X -Y Q2 -X -Y Q3 -X +Y Q4 +X +Y

**How fast are we going?**

For calculating the speed for every change in mouse coordinates(X,Y) record the time since the last coordinate change. Hint: use the timer counter as a stop watch. A slow circle will take longer...

I will leave it to you to use google to find out how to get the mouse coordinates (mousemove event) and set up and read a timer to measure the time between events.

Good Luck!