如何在R饼图中重叠多个值？

install.packages("ggplot2")
library(ggplot2)

data <- data.frame(category = c("A", "B", "C", "D"),
                   value = c(30, 20, 15, 35))

p <- ggplot(data, aes(x = "", y = value, fill = category)) +
  geom_bar(stat = "identity", width = 1) +
  coord_polar(theta = "y") +
  theme_void()

print(p)

data <- rbind(data,
              data.frame(category = c("E", "F", "G", "H"),
                         value = c(10, 25, 20, 15)))

p <- ggplot(data, aes(x = "", y = value, fill = category)) +
  geom_bar(stat = "identity", width = 1) +
  coord_polar(theta = "y") +
  scale_fill_manual(values = c("red", "blue", "green", "yellow")) +
  theme_void()

print(p)