diff --git a/Makefile b/Makefile
index 363a33c..c219836 100644
--- a/Makefile
+++ b/Makefile
@@ -2,7 +2,7 @@ SRC        := $(wildcard *.tex)
 OBJPDF     := $(SRC:tex=pdf)
 RM         := rm --force 
 TEXPDFPRG  := xelatex
-TEXPDFOPT  := -file-line-error  
+TEXPDFOPT  := -file-line-error -shell-escape
 DATE       := `date +'%d%m%Y-%H%M%S'`
 BUILDLOG   := build-messages-$(DATE).txt
 LATEXBUILD := $(TEXPDFPRG) $(TEXPDFOPT)