diff --git a/01.curriculum/01.physics-chemistry-biology/02.Niv2/04.optics/04.use-of-basic-optical-elements/01.plane-refracting-surface/02.plane-refracting-surface-overview/cheatsheet.en.md b/01.curriculum/01.physics-chemistry-biology/02.Niv2/04.optics/04.use-of-basic-optical-elements/01.plane-refracting-surface/02.plane-refracting-surface-overview/cheatsheet.en.md
index 194d86481..c9eae0075 100644
--- a/01.curriculum/01.physics-chemistry-biology/02.Niv2/04.optics/04.use-of-basic-optical-elements/01.plane-refracting-surface/02.plane-refracting-surface-overview/cheatsheet.en.md
+++ b/01.curriculum/01.physics-chemistry-biology/02.Niv2/04.optics/04.use-of-basic-optical-elements/01.plane-refracting-surface/02.plane-refracting-surface-overview/cheatsheet.en.md
@@ -79,7 +79,7 @@ refracting interface corresponds to two different plane refracting surfaces :<br
 #### Non stigmatism of spherical refracting surfaces
 
 Ray tracing study of a **spherical refracting surface** :
-[Click here for geogebra animation](https://www.geogebra.org/material/iframe/id/zqwazusz)<br>
+[Click here for geogebra animation](https://www.geogebra.org/material/iframe/id/x4hxqekd)<br>
 
 * **At each impact point** of the rays upon the spherical refracting surface, the **Snell-Descartes relation applies**.