translate([-clip_wall+clip_top_xoff, -clip_space/2-clip_wall, clip_l])
cube([clip_wall+epsilon, 2*clip_wall+clip_space, epsilon]);
};
translate([-clip_wall+clip_top_xoff, -clip_space/2-clip_wall, clip_l])
cube([clip_wall+epsilon, 2*clip_wall+clip_space, epsilon]);
};