Simple DC Motor DIY STEM Kit
$9.99$5.55
Very roughly a surface is orientable if it has two sides so that, for example, is
it possible to paint it with two different colours. A sheet of paper or the
surface of a sphere are examples of orientable surfaces. A Mobius strip is a
non-orientable surface: you can build one with a strip of paper (twist the strip
and glue end together to form a ring) and verify that it has only one side: it is
not possible to paint it with two colours.
'An expert is someone who knows some of the worst mistakes that can be made in his subject and how to avoid them.'