#
# plot a color strip
#
plot.new()
plot.window(xlim = c(0, 6), ylim = c(0, 6), asp = 1)
for(i in 1:6) rect(i-1, i-1, i, i, col = "indianred")
for(i in 1:5) rect(c(i,i-1), c(i-1,i), c(i+1,i), c(i,i+1), col = c("orange","purple"))
for(i in 1:4) rect(c(i-1,i+1), c(i+1,i-1), c(i,i+2), c(i+2,i), col = c("violet","yellow"))
for(i in 1:3) rect(c(i+2,i-1), c(i-1,i+2), c(i+3,i), c(i,i+3), col = c("forestgreen","dodgerblue"))
for(i in 1:2) rect(c(i+3,i-1), c(i-1,i+3), c(i+4,i), c(i,i+4), col = c("dodgerblue","forestgreen"))
rect(c(5,0), c(0,5), c(6,1), c(1,6), col = c("violet","yellow"))
