def show_frames(flags, data):
    """
    Returns a list of meshes of coordinate axes that have been transformed to represent the camera matrix
    at each --every:th frame.

    flags: Command line arguments
    data: dict with keys ['poses', 'intrinsics']
    returns: [open3d.geometry.TriangleMesh]
    """
    frames = [o3d.geometry.TriangleMesh.create_coordinate_frame().scale(0.25, np.zeros(3))]
    for i, T_WC in enumerate(data['poses']):
        if not i % flags.every == 0:
            continue
        print(f"Frame {i}", end="\r")
        mesh = o3d.geometry.TriangleMesh.create_coordinate_frame().scale(0.1, np.zeros(3))
        frames.append(mesh.transform(T_WC))
    return frames