# Ideal external gear pair: no loss, backlash or tooth strength
driverTeeth = 20 in 10..60
drivenTeeth = 60 in 20..120
inputSpeed = 1200 rpm in 100..3000
ratio := drivenTeeth / driverTeeth
outputSpeed := inputSpeed / ratio [rpm]
check ratio requirement: ratio >= 2
scenario faster: inputSpeed = 1800 rpm