雑なコード.R

library(tidyverse)

# parameters ---------
steps <- 10000L
coil_turns <- 20L
rotation <- pi/2
coil_waviness <- 100
wave_height <- 1.5


# image --------

library(httr)
res <- GET("http://hoxo-m.com/img/team/makiyama.png")
img <- content(res)

f <- function(x, y) {
  3 - sum(img[128 - floor(y), 128 - floor(x),])
}


# data  ----------------

d <- tibble(
  t = 2 * pi * seq(0, steps) / steps * coil_turns,
  phi = t - rotation,
  m = sin(t * 10/7),
  x_orig = (cos(phi) + t * sin(phi)) / 2 / max(t) * 128 + 64,
  y_orig = (sin(phi) - t * cos(phi)) / 2 / max(t) * 128 + 64,
  f_val = purrr::map2_dbl(x_orig, y_orig, f),
  x = x_orig + f_val * wave_height * sin(phi * coil_waviness) * sin(phi),
  y = y_orig - f_val * wave_height * sin(phi * coil_waviness) * cos(phi)
)


# plot -------------------

ggplot(d) +
  geom_path(aes(x, y)) +
  theme_minimal() +
  coord_equal()