triangles <- function(x,y,z,conn){
  rgl.clear()
  len <- length(x)
  for(i in 1:len){
    j <- i+1
    if( j > len ){
      j <- j-len
    }
    rgl.lines( c(x[i],x[j]), c(y[i],y[j]), c(z[i],z[j]), color="blue",size=2)
  }
  len <- ncol(conn)
  for(i in 1:len){
    c <- conn[,i]
    xx <- c( x[c[1]+1], x[c[2]+1], x[c[3]+1] )    
    yy <- c( y[c[1]+1], y[c[2]+1], y[c[3]+1] )    
    zz <- c( z[c[1]+1], z[c[2]+1], z[c[3]+1] )
    rgl.triangles( xx, yy, zz, color="red")
  }
}

main <- function(){
  xyz <- rbind(
           c( 1.0,     0.0,    0.2),
           c( 0.0,     0.2,    0.0),
           c(-1.0,     0.0,   -0.2),
           c(-0.5,    -0.707,  0.2),
           c( 0.1414, -0.1,    0.0),
           c( 0.5,     0.707, -0.2),
           c(-0.5,     0.707,  0.2),
           c(-0.1414, -0.1,    0.0),
           c( 0.5,    -0.707, -0.2) )
  conn <- cbind(
           c( 0, 4, 8),
           c( 0, 1, 4),
           c( 1, 5, 4),
           c( 1, 6, 5),
           c( 1, 7, 6),
           c( 1, 2, 7),
           c( 7, 2, 3),
           c( 7, 3, 4),
           c( 4, 8, 7) )

  triangles( xyz[,1], xyz[,2], xyz[,3], conn)
}