extract obj_props
return {
    make_ref_grid: (s, scaling) {
        ref_grid_off = [300, 900]
        ref_grid_main = ?g
        ref_grid_center = ?g

        $.add(obj {
            OBJ_ID: 211,
            SCALING: 0.3,
            X: ref_grid_off[0] + ((s - 1) / 2) * 30 * scaling,
            Y: ref_grid_off[1] + ((s - 1) / 2) * 30 * scaling,
            GROUPS: ref_grid_center,
        })

        let ref_grid = []
        

        for x in ..s {
            let column = []
            
            for y in ..s {
                group = ?g
                $.add(obj {
                    OBJ_ID: 211,
                    SCALING: 0.3,
                    X: ref_grid_off[0] + x * 30 * scaling,
                    Y: ref_grid_off[1] + y * 30 * scaling,
                    GROUPS: [group, ref_grid_main],
                })
                column.push(group)
                
            }
            ref_grid.push(column)
        }
        return {ref_grid, ref_grid_main, ref_grid_center}
    },

    make_follow_frame: (s) {
        let follow_frame = []

        for x in ..s {
            let follow_column = []
            for y in ..s {
                follow_column.push(?g)
            }
            follow_frame.push(follow_column)
        }
        return follow_frame
    }
}