Gradient/Percent

The next step was how to determine what makes these shapes 3D.

Each individual pixel is the same size, the x and y coordinates remain the same as each other regardless of the scale. In order to make these 3D I needed to introduce a z axis. The only thing that differs is the gradient of each pixel. The gradient is a percentage of each pixel that is taken up by black. If 75% of the pixel is taken up by black and 25% by white, the overall gradient of the will be 75% (if white is 0% and black 100%)

So I found the gradient of each pixel to represent the z axis.