diff --git a/Karto/README-why.md b/Karto/README-why.md
index 75b0b82..eff6563 100644
--- a/Karto/README-why.md
+++ b/Karto/README-why.md
@@ -1,3 +1,5 @@
 - cannot measure an angle between xline and polyline. "xline is not a line".
-- inserting a block takes up 2 layers: the one that the block was created in, and
-  where it was inserted.
+- inserting a block takes up 2 layers: the one that the block was created in,
+  and where it was inserted.
+- imagine adding 11 donuts. made 1 mistake, want to try again. Undo doesn't
+  work. If escaped from donut insertion mode, undo will remove all donuts.
diff --git a/Karto/assignment5/KTZ004_2019_05_brez.dwg b/Karto/assignment5/KTZ004_2019_05_brez.dwg
index 846af4c..67fd7ea 100644
Binary files a/Karto/assignment5/KTZ004_2019_05_brez.dwg and b/Karto/assignment5/KTZ004_2019_05_brez.dwg differ