Left click to add/move a point.
Right click to pan.
Scroll to zoom.
Click to add points
To turn a set of points into a polynomial, first plug in each point into the equation
axn + bxn-1 + ... + z = y
where n is the number of points minus one, or the polynomial's degree, and x and y are the points position on the graph. Solve the system of equations to find each coeficient. I use an algoritihm to transform the corresponding matrix into row reduced echelon form. Once the equation is found, it is easy to plot.