diff --git a/Zframework/mathExtend.lua b/Zframework/mathExtend.lua
index 9eb5786b..85249212 100644
--- a/Zframework/mathExtend.lua
+++ b/Zframework/mathExtend.lua
@@ -1,5 +1,6 @@
 local MATH={}for k,v in next,math do MATH[k]=v end
 
+local int,ceil=math.floor,math.ceil
 local rnd=math.random
 
 MATH.tau=2*math.pi
@@ -20,10 +21,6 @@ function MATH.coin(a,b)
     end
 end
 
-function MATH.lerp(s,e,t)
-    return s+(e-s)*t
-end
-
 function MATH.interval(v,low,high)
     if v<=low then
         return low
@@ -34,6 +31,18 @@ function MATH.interval(v,low,high)
     end
 end
 
+function MATH.lerp(s,e,t)
+    return s+(e-s)*t
+end
+
+do--function MATH.listLerp(list,t)
+    local interval,lerp=MATH.interval,MATH.lerp
+    function MATH.listLerp(list,t)
+        local t2=(#list-1)*interval(t,0,1)+1
+        return lerp(list[int(t2)],list[ceil(t2)],t2%1)
+    end
+end
+
 function MATH.expApproach(a,b,k)
     return b+(a-b)*2.718281828459045^-k
 end