diff --git a/pmwiki_recipes/exercises.php b/pmwiki_recipes/exercises.php
index 9ec4af7..ea7a2d2 100644
--- a/pmwiki_recipes/exercises.php
+++ b/pmwiki_recipes/exercises.php
@@ -4,22 +4,22 @@
 Generate exercises based on wiki content and its structure
  
 exercises idea to implement (cf http://fabien.benetou.fr/Cookbook/Cognition#DailyExercisesFeed )
- 	random type is not implemented properly enough for score tracking
-		e.g. highest score from random appear as other exercise
-		after 1 random exercise, going back to the same type of the last picked exercise
 	which of those group corresponds the graph visualization V, A, B or C? 
 		using groupnetworkvisualization.php
 	what is the correct order for pages A, B and C on descending criteria i A>B>C? A>C>B? B>C>A? B>A>C? C>B>A? C>A>B?
 		e.g. size, frequency update, last edition, ... 
 	what is the color hashing used in RevertedPIM for this group, color A, B or C?
 		might require JS
-	keyword or URL in pages
 	definition of word and vice versa
 		limited to pages with definitions (e.g. some languages)
 			list lines with "* word = definition"
 			split word and definition
 			pick one and display the other with alternatives
 		extend type=pagehasexpression
+		keyword or URL in pages or specific "word" per type
+	which of those update visualizations VA, VB or VC corresponds the page P ? (invert of type=historyvisualization)
+	note that overall most exercise which is about assign a set to another have a mirror
+		this mirror might have a completely different difficulty though
 difficulty parameter
 	should be linked to the counter
 	e.g. increasing the number of possibilities (at least 1 out of 5 pages instead of at least 1 out of 3)
@@ -28,16 +28,30 @@ do a graph traversal rather than random jumps
 	i.e. if pick randomly from the linked pages or from the group or from the the whole wiki of the previous page
 	consider https://research.cc.gatech.edu/inc/game-forge 
 improve parsing
-	discard more pages
-		structuring e.g. PmWiki. , RecentChanges, GroupFooter, GroupHeader, Template, ...
-		page with just one line, especially markups, typically redirections
+	page with just one line, especially markups, typically redirections
+filters
+	structuring e.g. PmWiki. , RecentChanges, GroupFooter, GroupHeader, Template, ...
+	strictly limited to "new" pages (e.g. less than a month ago)
+	strictly limited to "old" pages (e.g. more than 2 years ago)
+support bias
+	X% of page from an existing filter
+		e.g. 80% of "new" pages
 support other interfaces
-	e.g. http://www.cs.cmu.edu/~listen/ listed in Content/Education#SeeAlso
+	e.g. http://www.cs.cmu.edu/~listen/ listed in http://fabien.benetou.fr/Content/Education#SeeAlso
+		ideally also more visual, animated, ...
 	Vimperator with predictable link numbers to go faster
 track time require for answering each question
 	display a clock
 	could improve excitment, e.g. answer the maximum number of questions correctly in X minutes
-	
+better manage the whole process	
+ 	random type is not implemented properly enough for score tracking
+		e.g. highest score from random appear as other exercise
+	random type happens just once, not as a sequence like the other types
+	mix types
+		support non equally divided session
+			e.g. 50% of exercice type A, 30% type B, 10% C and 10% D
+		dynamically divise based on score history
+			e.g. 40% of exercice type B with the lowest high score, 30% D with 2nd lowest high score, 20% A with difficulty increase, 10% C diff++
 
 implemented
 	is word X from page A, B, C or D? (type=expressioninpage)
@@ -64,6 +78,7 @@ function Exercises($pagename, $auth){
 		$availableexercisetypes[] = "historyvisualization";
 
 	if ($type=="random" || $type=="") {
+		// XXX after 1 random exercise, going back to the same type of the last picked exercise
 		$type= $availableexercisetypes[array_rand($availableexercisetypes)];
 		$random=true;
 	}
@@ -439,7 +454,7 @@ function ExercisesResults(){
 		// could instead filter by exercise and sort by highest score, listing the top3 score per per exercise
 		$past_scores .= "<table><tr>";
 		foreach ($availableexercisetypes as $exercisetype){
-			$past_scores .= "<td><a href=\"AllPages/AllPages?action=Exercises&type=$exercisetype\">$exercisetype</a></td>";
+			$past_scores .= "<td><a href=\"n=AllPages.AllPages&action=Exercises&type=$exercisetype\">$exercisetype</a></td>";
 		}
 		$past_scores .= "</tr><tr>";
 		foreach ($availableexercisetypes as $exercisetype){