Ecco la rappresentazione grafica del triangolo (con R):

```# la scala
x <- c(-1,8); y <- c(-1,8) ; z1 <- c(-1,8)
# il tracciamento del box (in una opportuna scala)
z <- array(rep(z1[1],4), dim=c(2,2)); th <- 30; ph <- 15
F <- persp(x,y,z,theta=th,phi=ph, scale=FALSE, zlim=z1,xlim=x,ylim=y,
ticktype="detailed",nticks=3,d=3)
# quello degli assi
figura <- function(F) {
lines(trans3d(c(0,0),c(0,0),c(0,z1[2]),pmat=F),col="red")
lines(trans3d(c(0,x[2]),c(0,0),c(0,0),pmat=F),col="red")
lines(trans3d(c(0,0),c(0,y[2]),c(0,0),pmat=F),col="red")
lines(trans3d(c(0,0),c(0,0),c(z1[1],0),pmat=F),col="red",lty=3)
lines(trans3d(c(x[1],0),c(0,0),c(0,0),pmat=F),col="red",lty=3)
lines(trans3d(c(0,0),c(y[1],0),c(0,0),pmat=F),col="red",lty=3)
# quello della figura
lines(trans3d(c(2,1),c(0,-1),c(1,2),pmat=F),col="blue")
lines(trans3d(c(2,3),c(0,3),c(1,8),pmat=F),col="blue")
lines(trans3d(c(1,3),c(-1,3),c(2,8),pmat=F),col="blue") }
figura(F)
#
z <- array(rep(z1[1],4), dim=c(2,2)); th <- 0; ph <- 0
F <- persp(x,y,z,theta=th,phi=ph, scale=FALSE, zlim=z1,xlim=x,ylim=y,
ticktype="detailed",nticks=3,d=3)
figura(F)
#
z <- array(rep(z1[1],4), dim=c(2,2)); th <- 0; ph <- 90
F <- persp(x,y,z,theta=th,phi=ph, scale=FALSE, zlim=z1,xlim=x,ylim=y,
ticktype="detailed",nticks=3,d=3)
figura(F)

```