It's to help speed me up when painting plein air and just tune my skills generally.
Tried thick and thin paint and moving the lamp around to create different shadow shapes. Each time I painted the pear I saw more, like a different tone or shape.
I focused on the planes of the pear - the surface areas, this helped simplify the subject.
My students will be trying this next week, let's hope they enjoy it, as I think its a really useful exercise :-)