diff --git a/docs/todo/core.md b/docs/todo/core.md
index c6b5273..26c2ae1 100644
--- a/docs/todo/core.md
+++ b/docs/todo/core.md
@@ -2,6 +2,9 @@
 
 * [] Reset board's size
 * [] Keep two decimals
+* [] Limit element's angle between -360~360 deg
+* [] Check if the element and elements' attribute of desc is supported
+* [] Suport elements'desc and attribute check method
 * [x] Scale canvas
 * [x] Scroll canvas
 * [x] Render by requestAnimateFrame