nsprings <- 2
pi <- c(0.5, 0.5)
vel <- c(6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,12,12,12,12,12, 12,12,12,12,12,12,12,12,12,12,12,12,12,12,12)