;圆转圆环mini_circle_2_donut
(defun c:mini_circle_2_donut( / old_cmd ss e x pp)
    (mini_start nil)
    (setq ss (mai_select_first '((0 . "CIRCLE")) "选择要变Donut的Circle实体:" "没有找到Circle实体."))
    (foreach x (mai_ssget_2_list ss)
       (setq pp (mai_get_property x)
	         e (mai_data_entget x)
	   )
       (mai_entmake "donut" (list (car e) (* 2. (cadr e)) 0))
       (mai_put_property (entlast) pp)
       (entdel x)
    )
    (mai_end)
)