$fn=64;

// --- Parameters ---
tile_size = 100;          // Width and height of the modular tile
tile_thickness = 15;      // Total thickness of the tile
rail_depth = 5;           // Depth of the mounting rail cutout
solid_mid_layer = 2;      // Thickness of the solid layer between rails and grid
grid_spacing = 4;         // Spacing between pin holes
grid_wall = 1;            // Thickness of the walls between pin holes

// Derived parameters
hole_size = grid_spacing - grid_wall;
grid_depth = tile_thickness - rail_depth - solid_mid_layer;
start_offset = grid_wall / 2;

module pinboard_tile() {
    difference() {
        // Main tile body
        cube([tile_size, tile_size, tile_thickness]);

        // Pinboard waffle grid
        // Subtracted from the front face to create a dense mesh for pins
        // Edges have exactly half a wall thickness so they tile seamlessly
        for(x = [start_offset : grid_spacing : tile_size - hole_size]) {
            for(y = [start_offset : grid_spacing : tile_size - hole_size]) {
                translate([x, y, rail_depth + solid_mid_layer])
                    cube([hole_size, hole_size, grid_depth + 1]);
            }
        }

        // Upper rail mount (ArtArsenal / French Cleat style)
        translate([0, tile_size - 30, 0])
            rail_cutout(tile_size);

        // Lower rail mount for stability
        translate([0, 20, 0])
            rail_cutout(tile_size);
    }
}

module rail_cutout(w) {
    // Creates a 45-degree upward-sloping cavity for wall rails
    hull() {
        // Opening at the back surface
        translate([-1, 0, -0.1])
            cube([w + 2, 15, 0.1]);
            
        // Deepest part of the pocket, shifted UP by 5mm to create the locking hook
        translate([-1, 5, rail_depth])
            cube([w + 2, 15, 0.1]);
    }
}

// Generate the model
pinboard_tile();