void mainImage(out vec4 fragColor, in vec2 fragCoord){
    float Size = 16.0;
    float Level2Size = 128.0;
	vec4 BaseColor = vec4(0.3, 0.3, 0.3, 1.0);
    vec4 AddColor = vec4(0.7,0.7,0.7, 1.0);
    
    vec2 Pos = floor(fragCoord / Size);
    vec2 Pos2 = floor(fragCoord / Level2Size);
    
    
    
    float PatternMask = mod(Pos.x + mod(Pos.y, 2.0), 2.0);
    float PatternMask2 = mod(Pos2.x + mod(Pos2.y, 2.0), 2.0);
    fragColor = BaseColor+ (max(PatternMask,PatternMask2)) * AddColor;
}