calendar heat map tetris chart

Modifying @baptiste's suggestion, if I do this:

calendar_tetris_geoms <- function() {
  list(
    geom_segment(aes(x=x, xend=x, y=ymin, yend=ymax)),                 # (a)
    geom_segment(aes(x=xmin, xend=xmax, y=y, yend=y)),                 # (b)
    geom_segment(aes(x=dec.x, xend=dec.x, y=dec.ymin, yend=dec.ymax)), # (c)
    geom_segment(aes(x=nye.xmin, xend=nye.xmax, y=nye.y, yend=nye.y)), # (d)
    geom_segment(x=-0.5, xend=51.5, y=7.5, yend=7.5),                  # put a line along the top
    geom_segment(x=0.5, xend=52.5, y=0.5, yend=0.5),                   # put a line along the bottom
    geom_text(aes(x=month.x, y=month.y, label=month.l), hjust=0.25)    # (e)
  )
}

Then this works a treat:

calendar_tetris_data(min(stock.data$date), max(stock.data$date)) %>% 
  left_join(stock.data) %>% 
  ggplot() + 
  geom_tile(aes(x=week, y=wday2factor(wday), fill = Adj.Close), colour = "white") + 
  calendar_tetris_geoms() + 
  facet_wrap(~ year, ncol = 1)