更改一个变量会以相同的方式更改所有其他变量

I have a JavaScript code which has 4 3-dimensional arrays that are each of 500x500x220 dimension (all 220 values in the last dimension are rarely all used). Because of this large dimension, it's much faster to define one array like this and then define the four arrays from that one. The problem is that then, when I change a value in one array, it changes in the others also. Here's my code:I have a JavaScript code which has 4 3-dimensio