diff -urN wf-/wf_ex.c wf/wf_ex.c
--- wf-/wf_ex.c	2015-12-21 00:00:00.000000000 +0900
+++ wf/wf_ex.c	2015-12-22 00:00:00.000000000 +0900
@@ -245,12 +245,25 @@
 		  }}
 		}};
 
+		data_t *merry_go_round = &(data_t){ type_op_data_set, &(struct op_data_set){
+		  .op = &(data_t){ type_arr, (data_t[]){
+		    { type_slide, &(d3_t){-20,20,0} },
+		    { type_copy_rot, &(struct copy_rot){ .n=8, .l=LINE_Z, .init_deg=0, .step_deg=45 } },
+		    { type_rot_way, &(struct rot_way){
+		      .l=LINE_Z, .deg_way={ .n=2, .vs=(double[]){0,360}, .ts=(double[]){10,0}, .ps=NULL, .dg=1 } } },
+		    { type_copy_timeshift, &(struct copy_timeshift){
+                      .n=3, .init_sec=0, .step_sec=2.0/3, .init={10+-3,-3,0}, .step={3,3,0} } },
+		    { type_slide_way, &(struct way){ .n=2, .ps=(pos_t[]){{0,0,0},{0,0,3}}, .ts=(double[]){2,2}, .vs=NULL, .dg=3 } },
+		    { type_end } }},
+		  .data = &(data_t){ type_cube }
+		}};
+
 		data.type = type_arr;
 		data.p = (data_t[]){
 			*axyz,
 			*cross,
 			*cube, *cube3,
-			*cup, *ferris_wheel,
+			*cup, *ferris_wheel, *merry_go_round,
 			{ type_end }
 		};
 	}