move notebooks to subdir

Makefile

@@ -1,6 +1,6 @@
 .PHONY: all clean
 
-HTMLS = $(patsubst %.ipynb,html/%.html,$(wildcard *.ipynb))
+HTMLS = $(patsubst notebooks/%.ipynb,html/%.html,$(wildcard notebooks/*.ipynb))
 
 badmathjax = "file:\/\/\/usr\/share\/javascript\/mathjax\/MathJax.js?config=TeX-AMS_CHTML-full,Safe"
 goodmathjax = "https:\/\/cdn.jsdelivr.net\/npm\/mathjax@2\/MathJax.js?config=TeX-AMS_CHTML"
@@ -10,8 +10,8 @@ all: $(HTMLS)
 clean:
 	rm -r html
 
-html/%.html: %.ipynb | html
-	jupyter nbconvert --to html $< --output $@ --execute
+html/%.html: notebooks/%.ipynb | html
+	jupyter nbconvert --to html $< --output $@ --execute --output-dir=.
 	sed -i 's/$(badmathjax)/$(goodmathjax)/' $@
 
 html: