$fn = 64;

// --- Parameters ---
tile_size = 60;          // Size of the square tile
base_height = 3;         // Height of the road surface
sidewalk_height = 2;     // Height of the sidewalk above the road
road_width = 30;         // Width of the road
corner_radius = 5;       // Radius of the intersection sidewalk corners

// Connector settings
connector_holes = true;  // Include holes for connecting pegs
hole_radius = 2.5;       // Radius for connection pegs
hole_depth = 4;          // Depth of connection holes

// --- Main Geometry ---
difference() {
    union() {
        // Main base (road level)
        translate([0, 0, base_height/2])
            cube([tile_size, tile_size, base_height], center=true);

        // Sidewalk blocks (four corners)
        for (rot = [0, 90, 180, 270]) {
            rotate([0, 0, rot])
                sidewalk_block();
        }
    }

    // Optional connector holes on all 4 sides
    if (connector_holes) {
        for (rot = [0, 90, 180, 270]) {
            rotate([0, 0, rot])
                translate([0, tile_size/2 + 0.1, base_height/2])
                rotate([90, 0, 0])
                cylinder(r=hole_radius, h=hole_depth + 0.1);
        }
    }
}

// --- Modules ---
module sidewalk_block() {
    // Slight Z overlap to ensure a manifold 3D-printable mesh
    z_overlap = 0.1;
    
    translate([0, 0, base_height - z_overlap]) {
        hull() {
            // Rounded corner facing the center of the intersection
            translate([road_width/2 + corner_radius, road_width/2 + corner_radius, 0])
                cylinder(r=corner_radius, h=sidewalk_height + z_overlap);

            // Far outer corner of the tile
            translate([tile_size/2 - 0.1, tile_size/2 - 0.1, 0])
                cube([0.1, 0.1, sidewalk_height + z_overlap]);

            // Edge along the Y-axis road
            translate([road_width/2, tile_size/2 - 0.1, 0])
                cube([0.1, 0.1, sidewalk_height + z_overlap]);

            // Edge along the X-axis road
            translate([tile_size/2 - 0.1, road_width/2, 0])
                cube([0.1, 0.1, sidewalk_height + z_overlap]);
        }
    }
}