This should get you started
library('tidyverse')
d = tibble(t = t, y1 = sp(t), y2 = figof8(t)) %>%
gather(f, c, -t) %>%
mutate(x = Re(c), y = Im(c))
d %>%
ggplot(aes(x = x, y = y, colour = f)) +
geom_path() +
theme_bw()
and then you can e.g. use numerical approximation to find curve intersections in the complex plane
