Teach 180: Did I Break Desmos? (Day 8)

We continued working with factorials and counting methods today in Calculus. Near the end of class a student asked what the graph of C(11,x) would look like?  Would it be like a parabola, going up and coming down? (Note: I love the students in my school for thinking like this and being willing to ask these questions.)  We quickly looked at a table of values and noted that the values went up and then back down as x changed from 0 to 11.  Then, I said "We have 2 minutes before the bell rings.  Let's look at the graph in Desmos."  Here is what we got.

Wait a minute!!!  What is going on here??? Why does this look like a step function???  Why is it plotting values for non-integer values of x???  Did I break Desmos???  At that point the bell rang and I told my students that I would ask Desmos what was going on here.  And I know that on Monday they won't forget to ask me what the folks at Desmos said.