$fn=64;

// Parameters
num_pens = 6;
pen_hole_diameter = 14;
cup_height = 90;
cup_diameter = 60;
base_thickness = 4;
center_distance = 18;     // Distance from center of cup to center of pen holes
center_hole_diameter = 12; // Optional center hole to save material

difference() {
    // Main cup body
    cylinder(h=cup_height, d=cup_diameter);
    
    // Outer pen holes
    for (i = [0 : num_pens - 1]) {
        rotate([0, 0, i * (360 / num_pens)])
        translate([center_distance, 0, base_thickness])
        // Height is extended slightly to ensure clean manifold cut at the top
        cylinder(h=cup_height, d=pen_hole_diameter);
    }
    
    // Center weight-reduction hole
    translate([0, 0, base_thickness])
    cylinder(h=cup_height, d=center_hole_diameter);
}