diff --git a/4-window-aggregations/README.md b/4-window-aggregations/README.md
index 346c6c2..502a218 100644
--- a/4-window-aggregations/README.md
+++ b/4-window-aggregations/README.md
@@ -10,4 +10,6 @@ In this, we are going to answer some questions of interest to the medical staff
 - For each lifestage group of polar bears and for each year, which polar bear was the most active (most amount of steps per day)?
 - For every year, figure out which polar bear was the heaviest.
 - Find out which bears were more anxious (higher blood pressure) than average the day after New Year's Eve (probably because of fireworks)?
+
+If you're up for a challenge:
 - Which polar bear has the highest risk of becoming a diabetic? (polar bears have a higher risk of becoming diabetic after going through a high blood sugar level episode. An episode is defined as a three-day or longer period of an average daily bgl of 200 )