$fn = 64;

// --- Parametric Variables ---
tile_size = 60;
base_thickness = 6;
curb_height = 1.5;
road_width = 30;

// Peg hole dimensions for modular connections
peg_radius = 2;
peg_depth = 4;

// Derived road radius values
road_center_r = tile_size / 2;
road_inner_r = road_center_r - (road_width / 2);
road_outer_r = road_center_r + (road_width / 2);

union() {
    difference() {
        // Main tile base and sidewalks
        cube([tile_size, tile_size, base_thickness + curb_height]);

        // Cut out the 90-degree curved road surface
        translate([0, 0, base_thickness])
        difference() {
            cylinder(h = curb_height + 1, r = road_outer_r);
            translate([0, 0, -0.5])
            cylinder(h = curb_height + 2, r = road_inner_r);
        }

        // Cut out connector holes for modularity (Bottom & Top edges)
        for (x = [10, tile_size - 10]) {
            translate([x, 0, base_thickness / 2])
                rotate([90, 0, 0])
                cylinder(h = peg_depth * 2, r = peg_radius, center = true);
                
            translate([x, tile_size, base_thickness / 2])
                rotate([90, 0, 0])
                cylinder(h = peg_depth * 2, r = peg_radius, center = true);
        }
        
        // Cut out connector holes for modularity (Left & Right edges)
        for (y = [10, tile_size - 10]) {
            translate([0, y, base_thickness / 2])
                rotate([0, 90, 0])
                cylinder(h = peg_depth * 2, r = peg_radius, center = true);
                
            translate([tile_size, y, base_thickness / 2])
                rotate([0, 90, 0])
                cylinder(h = peg_depth * 2, r = peg_radius, center = true);
        }
    }

    // Raised dashed center line for easy painting/printing
    for (angle = [15 : 15 : 75]) {
        rotate([0, 0, angle])
        translate([road_center_r, 0, base_thickness])
        translate([-1, -3, 0])
        cube([2, 6, 0.4]);
    }
}