Here's another video that shows different ways silicon wafers are manufactured, including "silicon ribbon" which makes rectangular ribbons!

https://www.youtube.com/watch?v=8QKzS_w_Ko0

Silicon Ribbons begin at 10:10.

https://en.wikipedia.org/wiki/String_ribbon

>Ribbon solar cells are a 1970s technology most recently sold by Evergreen Solar (which is now in receivership, i.e. bankrupt and liquidated), among other manufacturers.

https://en.wikipedia.org/wiki/Crystalline_silicon#PV_industr...

>ribbon silicon (ribbon-Si), has currently no market