How to create smooth animated hover background followoing pointer

I want to create a product list on much box, i want something different from others, and i found that. Here's something product list i want to create : http://dunked.com/showcase As you see on second product list, their can move the hover background smoothly, and the different is that hovered background follow the pointer in 4 directions (up, right, down, left). I see another sample like this, but its only 2 direction (right to left and left to right) [https://jsfiddle.net/zv2gb78L/][2] Can someone help me what the algorithm their use to create that? or you can show me something like that. Thanks in advance