Blue ran 100 m south then 50 m north

all togather becomes 150 m

or 150 ×100cm = 15000cm

the first american roller coaster was the mauch chunk switchback railway, built in the mountains of pennsylvania in the mid-1800s. the track, originally built to send coal to a railway, was reconfigured as a "scenic tour."

wavelength divides in half and speed stays the same.