void main()
{
    const mat4 tempMat = mat4(1,0,0,1,1,0,1,0,0,0,0,0,0,0,0,0);

    int i = 0;
    int j = 1;

    vec4 v6 = tempMat[i,j]; 
    vec4 v8 = tempMat[j,2]; 
    mat4 m = mat4(1,0,0,1,1,0,1,0,0,0,0,0,0,0,0,0);
    vec4 v10 = m[j]; // 1,0,0,1 
    vec4 v11 = m[j,2]; 
    vec4 v12 = m[2,j]; 
     

    gl_FragColor = v6 + v8 + v10 + v11 + v12; 
}