diff --git a/chapter.mk b/chapter.mk
index 7d8f918..7bed524 100644
--- a/chapter.mk
+++ b/chapter.mk
@@ -3,6 +3,7 @@ plots : pythonplots gnuplots
 
 # python plots:
 PYFILES=$(wildcard *.py)
+PYFILES := $(filter-out dattomat.py, $(PYFILES))
 PYPDFFILES=$(PYFILES:.py=.pdf)
 
 pythonplots : $(PYPDFFILES)