diff --git a/resources/graphics/minus.png b/resources/graphics/minus.png
new file mode 100644
index 0000000..a5d869a
--- /dev/null
+++ b/resources/graphics/minus.png
diff --git a/resources/graphics/plus.png b/resources/graphics/plus.png
new file mode 100644
index 0000000..88aa52f
--- /dev/null
+++ b/resources/graphics/plus.png