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;

wall_height = 60;

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

//projection(cut = false) {
    union() {
        //wall
        cube([wall_height, cell_size, wall_j_length]); 
        
        translate([-wall_j_height, cell_size/2,0])
            //joint
            cube([wall_j_height, wall_j_length, wall_j_width]);
    }
//}