3D chart

R code of the ggplot2 example

library(ggplot2)
library(dplyr)
library(palmerpenguins)

## Bars drawn as boxes in oblique perspective: a front face that carries
## the count, a top and a side whose depth codes nothing.
dx <- 0.15
dy <- 14
bars <- penguins |>
  count(island) |>
  mutate(x = seq_along(island), l = x - 0.2, r = x + 0.2)
face <- function(kind, xs, ys) {
  bind_rows(lapply(seq_len(nrow(bars)), function(i) {
    tibble(island = bars$island[i], kind = kind, x = xs(bars[i, ]), y = ys(bars[i, ]))
  }))
}
faces <- bind_rows(
  face("side", \(b) c(b$r, b$r + dx, b$r + dx, b$r), \(b) c(0, dy, b$n + dy, b$n)),
  face("top", \(b) c(b$l, b$r, b$r + dx, b$l + dx), \(b) c(b$n, b$n, b$n + dy, b$n + dy)),
  face("front", \(b) c(b$l, b$r, b$r, b$l), \(b) c(0, 0, b$n, b$n))
) |>
  mutate(group = paste(island, kind))

p <- ggplot(faces, aes(x = x, y = y, group = group, fill = kind)) +
  geom_polygon(colour = "white", linewidth = 0.3) +
  scale_fill_manual(values = c(front = "#9b2367", top = "#c97aa5", side = "#6b1847"), guide = "none") +
  scale_x_continuous(breaks = bars$x, labels = bars$island) +
  scale_y_continuous(labels = lex_number, expand = expansion(mult = c(0, 0.05))) +
  labs(title = "Nearly half of the penguins were sampled on Biscoe Island",
       subtitle = "Penguins by island; the bars' depth codes nothing",
       x = NULL, y = "Penguins",
       caption = "Data: palmerpenguins (Horst, Hill & Gorman 2020)") +
  theme_lex_viz(grid = "y", arrows = "y")