How an octagon be equiangular but not equilateral?

You can do it in a way that is similar to making a square into a rectangle. Take a regular octagon - which has equal angles and equal sides. Grab a pair of opposite sides and pull apart. The angles will not change but two of the sides will be longer than the others. The above process can be repeated with each pair of opposite sides so that you end up with four pairs of sides with different lengths. It is possible to have all eight sides different but the process is somewhat more complicated.