diff --git a/chameleonic.p8 b/chameleonic.p8
index 6dca504..30b30c6 100644
--- a/chameleonic.p8
+++ b/chameleonic.p8
@@ -33,6 +33,44 @@ function gsv(s)
  return ret
 end
 
+function cycle(tbl,period)
+ period = period or 1
+ return tbl[t()%period*#tbl\period+1]
+end
+
+-- fake sprintf function
+-- %~ for literal "%"
+-- %v for param
+-- %! for tostring(param)
+--    which dumps tables
+function fmt(f, ...)
+ local out, i = "", 0
+ for s in all(split(f,"%")) do
+  if i == 0 then
+   -- before first format directive
+   out ..= s
+   i = 1
+  else
+   local m = s[1]
+   if m == "~" then
+    out ..= "%"
+   else
+    local p = select(i,...)
+    i+=1
+    if m == "v" then
+     out ..= p
+    elseif m == "!" then
+     out ..= tostring(p)
+    else
+     assert(false, tostr(m).."is not a formatting directive")
+    end
+   end
+   out ..=sub(s,2)
+  end
+ end
+ return out
+end
+
 mnames={}
 function names(root)
  local n=mnames[root]
@@ -241,14 +279,12 @@ function kbd:release(i)
 end
 
 function tostring(any)
- if type(any)=="table" then
-  local str = "{ "
-  for k,v in pairs(any) do
-      str=str..tostring(k).."->"..tostring(v).." "
-  end
-  return str.."}"
+ if (type(any)!="table") return tostr(any)
+ local str = "{ "
+ for k,v in pairs(any) do
+  str..=tostring(k).."->"..tostring(v).." "
  end
- return tostr(any)
+ return str.."}"
 end
 
 -->8
@@ -264,7 +300,7 @@ function title:draw()
  print("pyrex",32,73,7)
  print("[nyeogmi]",62,73,7)
  print("kistaro",32,79,7)
- local lvlstr = "⬅️ "..start_level.." ➡️"
+ local lvlstr = fmt("⬅️ %v ➡️",start_level)
  print(lvlstr,50,91,1)
  print(lvlstr,51,90,blinkcol) 
 end
@@ -434,8 +470,7 @@ function level:recollide_reanchor()
      not self:mcoll(mx1,my0) and
      not self:mcoll(mx1,my1)
     ) then
-     local key="GEOM"..mx0..","..my0..","..dx..","..dy
-     anch_new[key]= {
+     anch_new[fmt("GEOM%v,%v,%v,%v",mx0,my0,dx,dy)]= {
       max(mx0,mx1),max(my0,my1),adx=-dx,ady=-dy
      }
     end
@@ -443,10 +478,9 @@ function level:recollide_reanchor()
   end
 
   for _,cr in pairs(self._crates) do
-   local key="CRATE"..cr.id..","..dx..","..dy
    local mx0,my0=cr.mx,cr.my
    local mx1,my1=mx0+dx,my0+dy
-   anch_new[key]={
+   anch_new[fmt("CRATE%v,%v,%v",cr.id,dx,dy)]={
     max(mx0,mx1),max(my0,my1),adx=-dx,ady=-dy
    }
   end
@@ -1054,7 +1088,7 @@ function rope:draw(artificial_px,artificial_py)
    if (anch.ady>0) y-=1
   end
   rectfill(x-1,y-1,x+1,y+1,12)
-  print("ax="..n1.ax..",ay="..n1.ay,72,sy)
+  print(fmt("ax=%v,ay=%v",n1.ax,n1.ay),72,sy)
   sy+=7
 
   local n0=n1.prev
@@ -1787,8 +1821,6 @@ function hints:init()
  end
  menuitem(1,"get hint",function() level.hintlevel+=1 end)
  menuitem(2,"hide hints",function() level.hintlevel=0 end)
- -- debug mode: enable mouse
- poke(0x5f2d,1)
 end
 
 function shdprint(txt,x,y,c)
@@ -1796,16 +1828,10 @@ function shdprint(txt,x,y,c)
  print(txt,x,y,c)
 end
 
-hintflicker={7,10,9,8,8,9,10,7}
+hintflicker=split"7,10,9,8,8,9,10,7"
 function hints:draw2()
  pal()
- local c=hintflicker[t()%1*#hintflicker\1+1]
-  -- debug mode: mouse coord display
- if stat(34) != 0 then
-  local mousex, mousey = stat(32), stat(33)
-  print("x ("..mousex..", "..mousey..")",mousex,mousey,c)
- end
-
+ local c=cycle(hintflicker)
 
  for i,h in ipairs(self[level.ix]) do
   if (i > level.hintlevel) return
@@ -1815,6 +1841,32 @@ function hints:draw2()
  end
 end
 
+-->8
+-- debug mouse support
+
+debugmouse = {}
+
+-- comment this out to disable debug mode
+add(real_modules, debugmouse)
+
+function debugmouse:init()
+ poke(0x5f2d,1)
+end
+
+debugflicker=split"5,6,7,15,14,8,2,4,9,10,11,3,12,13"
+debugchs = split" ,x, ,□"
+
+function debugmouse:draw3()
+ if (stat(34) == 0) return
+ pal(15,cycle(debugflicker,1.5))
+ local x, y, c = stat(32), stat(33), cycle(debugchs,2)
+ if (c == " ") spr(50,x,y)
+ print(c,x,y,15)
+ local px, py = mid(0,x,89), mid(0, y > 111 and y - 12 or y + 6, 117)
+ print(fmt("(%v, %v)\n[%v, %v]",x,y,x\8,y\8),px,py,15)
+ pal()
+end
+
 __gfx__
 000030000000002200003000eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeff1ff1ff1fffffff1ffffff1fffffff1dddddddd111111110005000000000000
 003333300000332200333330eeffffffffffffffffffffeee5e555e55e555e5eff1ff1ffffffffffffffffffffffffffdddddddd111111110000500000000000
@@ -1840,10 +1892,10 @@ eeee0000cc04405500444400efeeee5e11111111e5eeeefeeeeeeeeeeeeeeeeeffffffffffffffff
 0a000aa4441a91a1bbabbbbbeffeeeeeeeeeeeeeeeeeeffeff1ff1ff11111111ff1111ff00000000000000000000000000000000000000000000000000000000
 00a0044449a110a1bbbbbbbbeeffffffffffffffffffffeeff1ff1ffffffffffffffffff00000000000000000000000000000000000000000000000000000000
 000aa111991111103bbbbbb3eeeeeeeeeeeeeeeeeeeeeeeeff1ff1ffffffffffffffffff00000000000000000000000000000000000000000000000000000000
-00000000991000000000000000000000000000000000000000000000000000000000000000000000000000000000000011111111111111111999999111111111
-00000000990000000000000000000000000000000000000000000000000000000000000000000000000000000000000019911991999999911999999119999999
-00000000990000000000000000000000000000000000000000000000000000000000000000000000000000000000000019977991999999911999999119999999
-00000000090000000000000000000000000000000000000000000000000000000000000000000000000000000000000019911991999117111991199111711999
+0000000099100000f765000000000000000000000000000000000000000000000000000000000000000000000000000011111111111111111999999111111111
+00000000990000007700000000000000000000000000000000000000000000000000000000000000000000000000000019911991999999911999999119999999
+00000000990000006060000000000000000000000000000000000000000000000000000000000000000000000000000019977991999999911999999119999999
+00000000090000005005000000000000000000000000000000000000000000000000000000000000000000000000000019911991999117111991199111711999
 00000000aa0000000000000000000000000000000000000000000000000000000000000000000000000000000000000019911991999117111991199111711999
 0000000077a000000000000000000000000000000000000000000000000000000000000000000000000000000000000019999991999999911997799119999999
 00000007777a00000000000000000000000000000000000000000000000000000000000000000000000000000000000019999991999999911991199119999999