What exactly is being shown in the animation/slideshow? You said its iterating and maximizing the MLE, but doesn't that just mean you're maximizing a single number? How can that iteration generate an entire heatmap?
The likelihood itself is a single number, but the algorithm is maximizing the likelihood based on a vector of 993 parameters representing the quality of a seat. Each x,y coordinate represents a seat in the ballpark, and each seat is mapped to one of those 993 values. The heatmap evolves as the vector approaches maximum likelihood.