The difference is the complexity of the concepts involved. There are predictable results when you e.g. combine and filter light spectra, stack several lenses an

The difference is the complexity of the concepts involved. There are predictable results when you e.g. combine and filter light spectra, stack several lenses and mirrors to make a telescope, mix two chemicals, put electric circuit components together, or perform a well-defined sequence of knitting stitches, but describing them is more difficult than whole-number arithmetic.