board_x = 5;
board_y = 5;
board_z = 0;

board_length = 1000;
board_width = 1000;

board_height = 12;

wall_j_width = 6;
wall_j_length = 6;
wall_j_height = 12;

cell_size = board_length/10;// it's equal to car width/length(will be fine if car be quadrat)

module board(x, y, z, length, width, height) {
    translate([x, y, z]) 
        color("orange") 
        cube([length, width, height]);
}

module set_board_nets(x, y, z, length, width, height) {
    for(i = [board_x + cell_size : cell_size/2 : (board_length)]) {
        for(j = [board_y + cell_size : cell_size/2 : board_width]){
                translate([i, j, 0])
                    color("red")
                    cube([length, width, height]);
        }
    }
}

module BoardWithNets() {
    difference() {
        board(board_x, board_y, board_z, board_length, board_width, board_height);
        set_board_nets(board_x, board_y, board_z+2, wall_j_width, wall_j_length, wall_j_height);
    }
}

module joint(tx, ty, coefficient1, coefficient2, coefficient3) {
    translate([tx, ty, 0]) color("black") cube([board_height * coefficient1, board_height * coefficient2, board_height * coefficient3]);
}
projection(cut = false) {
    union() {
        BoardWithNets();

        // Loop through regarding wich count joints I want to set side of my board, If I want to 3 joint need to set loop 1/4, 2/4, 3/4. if I want to 5 joint need to set this loop 1/6, 2/6, 3/6, 4/6, 5/6
        for (pos = [1/5, 2/5, 3/5, 4/5]) {
            offset = board_length * pos- board_height * 4;
        // Bottom & Top sides
            joint(board_x + offset, board_y - board_height, 8, 1, 1);
            joint(board_x + offset, board_y + board_width, 8, 1, 1);
        // Left & Right sides
            joint(board_x - board_height, board_y + offset, 1, 8, 1);
            joint(board_x + board_length, board_y + offset, 1, 8, 1);
        }
    }
}