clean code

src/island.ml

@@ -16,14 +16,9 @@ let get request =
       ~a:[ a_id "canvas" ]
       [ txt "please update your browser or enable javascript" ]
   in
-  let img_grass = mk_img "grass" in
-  let img_papy_bottom = mk_img "papy_bottom" in
-  let img_water = mk_img "water" in
+  let images = List.map mk_img [ "grass"; "papy_bottom"; "water" ] in
 
-  let page =
-    div ~a:[ a_class [ "centered" ] ]
-    @@ [ canvas; img_grass; img_papy_bottom; img_water ]
-  in
+  let page = div ~a:[ a_class [ "centered" ] ] @@ (canvas :: images) in
 
   let js =
     script