Design a compound spur gear train for a precise ratio of $90$:$1($increaser$).$ The pressure angel is $20,$ giving a minimum teeth number of $18.$ Make a sketch of the train and determine the size a box that can encompass the gear train. Use a diametral pitch of $6i{n}^{-1}.$

BONUS: design a simple spur gear train for a ratio of $10$:$1$ with a minimum teeth number of $18.$ Use a diametral pitch of $6i{n}^{-1}.$ Sketch the gear train, and find a box size.

Design the same gear train as in problem $5,$ but where all the stages are identical.