diff --git a/00.brainstorming-pedagogical-teams/45.synthesis-structuring/instructions-for-levels/30.beyond/annex.fr.md b/00.brainstorming-pedagogical-teams/45.synthesis-structuring/instructions-for-levels/30.beyond/annex.fr.md
index 6b28da736..57f3edcaf 100644
--- a/00.brainstorming-pedagogical-teams/45.synthesis-structuring/instructions-for-levels/30.beyond/annex.fr.md
+++ b/00.brainstorming-pedagogical-teams/45.synthesis-structuring/instructions-for-levels/30.beyond/annex.fr.md
@@ -80,9 +80,11 @@ Sont proposées les catégories suivantes, mais à débattre :
 ! I choose it
 !
 ! </summary>
-! A lensball is a simple physical system: a sphere of glass of refractive index $`n=1.5`$ and of radius $R=5\;cm$.
+! A lensball is a simple physical system: a sphere of glass of refractive index $`n=1.5`$ and of radius $`R=5\;cm`$.
 !
-! A ball lensball is placed in front of a painting. Depending on the position of the observer or the camera, the optical system (the sequence of simple optical elements crossed by light between the physical object and the observed image) that forms the image differs.
+! A ball lensball is placed in front of a painting. Depending on the position of the observer or the camera, 
+the optical system (the sequence of simple optical elements crossed by light between the physical object
+and the observed image) that forms the image differs.
 !
 ! Observe the 3 images of the painting given by the lensball :
 !
@@ -91,7 +93,8 @@ Sont proposées les catégories suivantes, mais à débattre :
 ! Images 2 (the smallest) and 3
 ! ![](lentille-boule-2-reflexions_L700.jpg)
 !
-! For each image of the painting, can you identify the optical system, then specify the characteristics of the various simple elements that constitute the system and their relative distances?
+! For each image of the painting, can you identify the optical system, then specify `
+the characteristics of the various simple elements that constitute the system and their relative distances?
 !
 ! * _The resolution time is the typical expected time to be allocated to this problem if it was part of an examen for an optics certificate._ 
 ! * _The discovery time is the expected time required to prepare this challenge if you don't have practice. But take as much time as you need._