diff --git a/src/Gargantext/Prelude.hs b/src/Gargantext/Prelude.hs
index 3b17e3a6215ab3a66553bd064960629f7116b75c..820054044eafb0ef22935468155fc4dce8747e5d 100644
--- a/src/Gargantext/Prelude.hs
+++ b/src/Gargantext/Prelude.hs
@@ -124,8 +124,11 @@ type Grain = Int
 type Step  = Int
 
 -- | Function to split a range into chunks
+-- if   step == grain then linearity
+-- elif step < grain then overlapping
+-- else dotted with holes
 chunkAlong :: Eq a => Grain -> Step -> [a] -> [[a]]
-chunkAlong a b l = case a > 0 && b > 0 && a >= b of
+chunkAlong a b l = case a > 0 && b > 0 of
     True  -> chunkAlong_ a b l
     False -> panic "ChunkAlong: Parameters should be > 0 and Grain > Step"
 
diff --git a/src/Gargantext/Viz/Phylo/Example.hs b/src/Gargantext/Viz/Phylo/Example.hs
index f1522bd22b14417604b28ff7b81cc6e4f4638a37..b79c0ea82ce3d67c2b05afb07d4eac8657001242 100644
--- a/src/Gargantext/Viz/Phylo/Example.hs
+++ b/src/Gargantext/Viz/Phylo/Example.hs
@@ -59,9 +59,9 @@ phyloTerms = toPeriodes date 5 3 $ cleanHistory  mapList phyloCorpus
 toPeriodes :: (Ord date, Enum date) => (event -> date)
      -> Grain -> Step -> [event] -> Map (date, date) [event]
 toPeriodes _ _ _ [] = panic "Empty history can not have any periods"
-toPeriodes f s o as = DM.fromList $ zip hs $ map (inPeriode f as) hs
+toPeriodes f g s es = DM.fromList $ zip hs $ map (inPeriode f es) hs
   where
-    hs = steps s o $ both f (DL.head as, DL.last as)
+    hs = steps g s $ both f (DL.head es, DL.last es)
 
 inPeriode :: Ord b => (t -> b) -> [t] -> (b, b) -> [t]
 inPeriode f h (start,end) =