Stone wall brick offset calculations

(Layers mod 2) equals zero at even layers 
and one for uneven layers.
wikipedia.org/wiki/Modulo_operation
Challenge: What other brick patterns can you make?

brick_length=5;
half_brick_length=brick_length/2;
brick_width=3;
brick_height=2;

for(layer=[0:1:5])
for(run=[0:1:5]){
shift= layer % 2; // <-- this is the sauce
translate(

[run*brick_length+shift*half_brick_length,

0,

layer*brick_height])

brick();
}

module brick(){color(rands(0,1,3)) 
cube([brick_length,brick_width,brick_height]);}