This is an illustration of what is possible to do with
`R`

and the `rgl`

library: a 3D knot.

With the `rgl`

package, you can make the image moove and
zoom in an out. Find this image in the interactive mode here.

```
# Library rgl
library(rgl)
#Choose the size of the image on the output (800,650 to have 800 x 600)
$windowRect <- c(0,50, 800, 650)
r3dDefaultsopen3d()
```

```
## glX
## 1
```

```
#If you want to put line on the background
#bg3d(sphere = TRUE, color = c("grey", "white"), lit = TRUE, back = "lines" ,lwd=2)
# This is to output a rgl plot in a rmarkdown document
# rgl::setupKnitr()
# plot
bg3d( col=rgb(0.2,0.8,0.5,0.8) )
<- seq(0, 2*pi, len = 50)
theta <- cylinder3d(
knot center = cbind(sin(theta) + 3*sin(2*theta), 2*sin(3*theta), cos(theta) - 2*cos(2*theta)),
e1 = cbind(cos(theta) + 4*cos(2*theta),6*cos(3*theta),sin(theta) + 4*sin(2*theta)),radius = 0.9,closed = TRUE)
shade3d(addNormals(subdivision3d(knot, depth = 2)), col = rgb(0.4,0.2,0.8,0.3))
# To display in an R Markdown document:
# rglwidget()
# save it as png
# snapshot3d( "~/Desktop/#20_portfolio_knot_3D.png", fmt="png")
# To save interactive plot to a file:
::saveWidget(rglwidget(width = 500, height = 500),
htmlwidgetsfile = "HtmlWidget/3dknot.html",
libdir = "libs",
selfcontained = FALSE
)
```