diff --git a/00.brainstorming-pedagogical-teams/45.synthesis-structuring/instructions-for-levels/30.beyond/annex.es.md b/00.brainstorming-pedagogical-teams/45.synthesis-structuring/instructions-for-levels/30.beyond/annex.es.md
index c0142fde4..a51988e76 100644
--- a/00.brainstorming-pedagogical-teams/45.synthesis-structuring/instructions-for-levels/30.beyond/annex.es.md
+++ b/00.brainstorming-pedagogical-teams/45.synthesis-structuring/instructions-for-levels/30.beyond/annex.es.md
@@ -206,6 +206,7 @@ Se ofrecen las siguientes categorías, pero para discusión, todas las ideas son
##### Algunos ejemplos
+
! *YOUR CHALLENGE* : An object (a painting), a physical system (a lensball), how many scenarios and optical systems?
!
! _Skill tested : understanding of physical situations_
@@ -214,7 +215,7 @@ Se ofrecen las siguientes categorías, pero para discusión, todas las ideas son
!
! *Discovery time : 30 minutes*
! *Resolution time : 10 minutes*
-
+!
!
!
! I choose it
@@ -234,48 +235,26 @@ Se ofrecen las siguientes categorías, pero para discusión, todas las ideas son
! Images 2 (the smallest) and 3
!
! 
-!
!
-!
-!
-! I choose it
-!
-! 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.
-!
-! Observe the 3 images of the painting given by the lensball :
-!
-! Image 1
-!
-! 
-!
-! Images 2 (the smallest) and 3
-!
-! 
-!
! 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._
+!
! <\details>
-!
-!
+!
!
! Ready to answer M3P2 team questions for image 1?
!
-!
-!
+!
+!
!
! Where is the painting located?
!
! * The painting is located on the other side of the lens, in relation to you.
!
-!
-!
+!
!
! What is the optical system giving the image of the painting?
!
@@ -283,8 +262,7 @@ Se ofrecen las siguientes categorías, pero para discusión, todas las ideas son
! * The optical system is composed of two spherical refracting surfaces, centered on the same optical axis.
!
!
-!
-!
+!
!
! How do you characterize each of the single optical elements that make up this optical system,
! and their relative distances?
@@ -303,83 +281,80 @@ Se ofrecen las siguientes categorías, pero para discusión, todas las ideas son
! $DS2$ encountered by the light has the follwing characteristics :
! $`\overline{S_2C_2}=-|R|=-5\;cm`$ ,
! $`n_{ini}=1.5`$ and $`n_{fin}=1`$
-!
+!
! * Algebraic distance between $DS1$ and $DS2$ is : $`\overline{S_1S_2}=+10\;cm`$
-!
+!
!
-!
-!
+!
!
! If you had to determine the characteristics of the image (position, size), how
! would you handle the problem?
!
-!
+!
! * $`DS1`$ gives an image $`B_1`$ of an object $`B`$. This image $`B_1`$ for $`DS1`$
! becomes the object for $`DS2`$. $`DS2`$ gives an image $`B'1`$ of the object $`B_1`$
-!
+!
!
!
-!
-!
+!
+!
+!
!
! Ready to answer M3P2 team questions for images 2 and 3?
!
-!
-!
+!
+!
!
! Where is the painting located?
!
-!
+!
! * The painting is located on the same side of the lens as you, behind you.
-!
+!
!
-!
-!
+!
!
-!
+!
! What are the two optical systems at the origin of the two images of the painting? And
! can you characterize each of the single optical elements (+ their relative distances)
! that make up each of these optical systems ?
!
-!
+!
! * A first optical system $`OS1`$ is composed of a simple convexe spherical mirror
! (the object is reflected on the front face of the ball lensball). Keaping the optical
! axis positively oriented in the direction of the incident light propagation on the lensball,
! the algebraic value of the mirror radius is : $`\overline{SC}=+5\;c`$.
-!
+!
! * The second optical system $`OS2`$ is composed of three simple optical elements :
! 1) The light crosses a spherical refracting surface $`DS1`$ with characteristics :
! $`\overline{S_1C_1}=+|R|=+5\;cm`$ , $`n_{ini}=1`$ and $`n_{fin}=1.5`$.
-!
+!
! 2) Then the light is reflected at the surface of the last lensball interface that
! acts like a spherical mirror of characteristics : $`\overline{S_2C_2}=-|R|=-5\;cm`$,
! $`n=1.5`$.
-!
+!
! 3) Finally the light crosses back the first interface of the lensball that acts
! like a spherical refracting surface those characteristics are :
! $`\overline{S_3C_3}=+|R|=+5\;cm`$ , $`n_{ini}=1.5$ and $n_{fin}=1`$.
-!
+!
! Relative algebraic distances between the different elements of $`OS2`$ are :
-!
+!
! $`\overline{S_1S_2}=+10\;cm`$ and $`\overline{S_2S_3}=-10\;cm`$
-!
+!
!
-!
-!
+!
!
! Which image is associated with each of the optical systems?
!
-!
+!
! * It is difficult to be 100% sure before having made the calculations.
-!
+!
!
-!
-!
+!
!
! Why do we had to take the picture in the darkness, with only the painting
! illuminated behind the camera, to obtain images 2 and 3 ?
!
-!
+!
! * At a refracting interface, part of the light incident power is refracted,
! and part is reflected. For transparent material like glass and for visible light,
! the part of the reflected power is small. If the room had been homogeneously
@@ -389,6 +364,7 @@ Se ofrecen las siguientes categorías, pero para discusión, todas las ideas son
!
!
+
! *YOUR CHALLENGE* : Looking at a cathedral through a lensball. Can you predict your observation?
!
! _Skill tested : to know how to carry out calculations_