1. Type your data (number of stones, height of water) one by one in the input bar.
2. Move the sliders a and b to fit a line to the data.
3. Use the equation of the line to refine your prediction.
4. Move the slider g to set the goal water level. (Pick a number between 14 and 16.)
5. Find the intersection point of the lines.

How many stones does the crow need?
What would change if the stones were smaller?
What would change if there was less water in the jar?