Answer:
It could be because you where hack. Or there was something wrong with the site that stopped it from saying why it stopped.
To make a horizontal line in mathematics you require some sort of constant function. Where no matter the input x the output y will always equal to a certain number n.
For eg. consider n = 2. Hence the graph of line has an equation of y = n making it always intercept in (x, n). As x increases the y is the same therefore the horizontal infinite line emerges.
So to plot or code this kind of program you need to have the same values of y therefore y is a constant function.
Hope this helps.
r3t40
I think it might be Heading & Border
