rect <-
  function (xleft, ybottom, xright, ytop, density = NULL, angle = 45,
            col = NULL, border = NULL,
            lty = NULL, lwd = par("lwd"), xpd = NULL, ...)
  {
    if (!is.null(density) && !is.null(angle)) {
      if (is.logical(border)) {
        if (border) border <- col
        else border <- NA
      }
      n <- range(length(xleft), length(xright),
                 length(ybottom), length(ytop))
      if (n[1] == 0)
        stop("invalid rectangle specification")
      n <- n[2]
      x <- rbind(rep(NA, n), xleft, xright, xright, xleft)[-1]
      y <- rbind(rep(NA, n), ybottom, ybottom, ytop, ytop)[-1]
      polygon(x, y, col=col, border=border, lty=lty, lwd=lwd, xpd=xpd,
              density=density, angle=angle, ...)
    }
    else
      .Internal(rect(as.double(xleft), as.double(ybottom),
                     as.double(xright), as.double(ytop),
                     col = col, border = border,
                     lty = lty, lwd = lwd, xpd = xpd, ...))
}