cool shader, what does it do?

shader.frag

#ifdef GL_ES
precision mediump float;
#endif

uniform vec2 u_resolution;
uniform vec2 u_mouse;
uniform float u_time;

float factor_x;
float factor_y;
vec2 opposing_factor;

void main() {
	vec2 st = gl_FragCoord.xy/u_resolution;
	vec2 mt = u_mouse/u_resolution;

	factor_x = abs(0.3 * cos(1.0 * u_time)/(st.x - 0.5));
	factor_y = abs(0.3 * sin(1.5 * u_time)/(st.y - 0.5));
	opposing_factor = vec2(step(1.0 - factor_x, 0.2), step(1.0 - factor_y, 0.2));

	gl_FragColor = vec4(step(factor_x, 0.5), step(factor_x * factor_y, 0.5), step(factor_y, 0.5),1.0);
}