# Create toy data frame
df <- data.frame(t = c(0, cumsum(runif(100, 0, 10))))
df$T <- (df$t)^0.5
df$S <- (cos(df$t * 0.1) + 1) * 5

# Quick peak
head(df, 10)
#>           t        T            S
#> 1   0.00000 0.000000 10.000000000
#> 2   9.82333 3.134219  7.775417364
#> 3  15.55317 3.943750  5.077395727
#> 4  19.09700 4.370011  3.337735036
#> 5  22.64978 4.759179  1.801216275
#> 6  23.12611 4.808962  1.621864060
#> 7  30.09085 5.485512  0.043831684
#> 8  31.18720 5.584550  0.001307812
#> 9  31.97788 5.654899  0.007892638
#> 10 39.18674 6.259932  1.435186018