Polygon inscribed into circles without ggplot2 or fmsb package

Question

I want to create some sort of radar chart but without using ggplot2 or fmsb.

Sample chart:

d1 <- 1:10
names(d1) <- LETTERS[1:10]

rChart <- function(N = 7, R = 1, border = NA, density = NA, angle = 45,
                        col = rgb(1, 0, 0, 0.5), lty = 2, lwd = 1){
  if (N >=3){
  alpha <- c(0, 2*pi*(1:N)/N)
  
  x <- R*cos(alpha)
  y <- R*sin(alpha)
  
  if (length(dev.list()) == 0){
      plot(x, y, type="n")
    }
  polygon(x, y, col = col, border = border, density = density, angle = angle)
  lines(x, y, lty = lty, lwd = lwd, col = col)
  }
}

# drawing two circles in one plot
rChart(N = 100, R = 8, density = 10, col = rgb(0, 1, 0, 0.4), lty = 2, lwd = 3)
rChart(N = 100, R = 6, density = 10, col = rgb(0, 1, 0, 0.4), lty = 2, lwd = 3)

Can I implement for loop to create polygon inscribed into circles and then place labels similiar as in the example above?