diff -urN wf-/Makefile wf/Makefile
--- wf-/Makefile	2015-12-17 00:00:00.000000000 +0900
+++ wf/Makefile	2015-12-20 00:00:00.000000000 +0900
@@ -2,6 +2,7 @@
 
 LIBS = -lm -lX11 -L/usr/X11R6/lib
 CFLAGS += -Wall -I/usr/X11R6/include
+#CFLAGS += -DDBG
 
 WF_OBJS = wf_ex.o data.o eye.o way.o d3.o x.o util.o key.o select.o
 
diff -urN wf-/data.c wf/data.c
--- wf-/data.c	2015-12-19 00:00:00.000000000 +0900
+++ wf/data.c	2015-12-20 00:00:00.000000000 +0900
@@ -1,6 +1,42 @@
 #include "x.h"
 #include "data.h"
 
+#ifdef DBG
+char *
+type_str(int type)
+{
+#define CASE_RET(type)	case type: return #type
+
+	switch(type){
+	CASE_RET(type_end);
+	CASE_RET(type_wire_frame);
+	CASE_RET(type_bar);
+	CASE_RET(type_cross);
+	CASE_RET(type_square);
+	CASE_RET(type_cube);
+	CASE_RET(type_arr);
+	CASE_RET(type_op_data_set);
+	CASE_RET(type_slide);
+	CASE_RET(type_zoom);
+	CASE_RET(type_zoom_and_slide);
+	CASE_RET(type_rot);
+	CASE_RET(type_point_symmetry);
+	CASE_RET(type_mirror);
+	CASE_RET(type_timeshift);
+	CASE_RET(type_slide_way);
+	CASE_RET(type_rot_way);
+	CASE_RET(type_copy);
+	CASE_RET(type_copy_rot);
+	CASE_RET(type_copy_point_symmetry);
+	CASE_RET(type_copy_mirror);
+	CASE_RET(type_copy_timeshift);
+	default: break;
+	}
+	return "???";
+}
+
+#endif /* DBG */
+
 void
 prm_set_eye_update(prm_t *prm, eye_t *eye)
 {
@@ -120,6 +156,10 @@
 void
 data_draw(data_t *data, prm_t *prm)
 {
+#ifdef DBG
+	fprintf(stderr, "%s() type=%s\r\n",
+		__func__, type_str(data->type));
+#endif
 	switch(data->type){
 	case type_wire_frame:
 		wire_frame_draw(data->p, prm);
@@ -152,9 +192,13 @@
 static void
 op_data_arr(data_t *op_arr, data_t *data, prm_t *prm)
 {
-	struct op_data_set set = { &op_arr[1], data };
-	data_t d = { type_op_data_set, &set };
-	op_data_draw(&op_arr[0], &d, prm);
+	if(op_arr[0].type == type_end) data_draw(data, prm);
+	else{
+		data_t arr = { type_arr, &op_arr[1] };
+		struct op_data_set set = { &arr, data };
+		data_t d = { type_op_data_set, &set };
+		op_data_draw(&op_arr[0], &d, prm);
+	}
 }
 
 static void
@@ -310,6 +354,10 @@
 {
 	prm_t bak = *prm;
 
+#ifdef DBG
+	fprintf(stderr, "%s() op.type=%s data.type=%s\r\n",
+		__func__, type_str(op->type), type_str(data->type));
+#endif
 	switch(op->type){
 	case type_arr:
 		op_data_arr(op->p, data, prm);
diff -urN wf-/wf_ex.c wf/wf_ex.c
--- wf-/wf_ex.c	2015-12-19 00:00:00.000000000 +0900
+++ wf/wf_ex.c	2015-12-20 00:00:00.000000000 +0900
@@ -205,11 +205,28 @@
 		    .n = 3, .init_sec = 0, .step_sec = -0.3, .init = {0,0,0}, .step = {0,0,0} } },
 		  .data = cube2 }};
 
+		data_t *cup = &(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=4, .l=LINE_Z, .init_deg=0, .step_deg=90 } },
+		    { type_rot_way, &(struct rot_way){
+		      .l=LINE_Z,
+		      .deg_way={ .n=2, .vs=(double[]){0,360*4}, .ts=(double[]){15,15}, .ps=NULL, .dg=3} } },
+		    { type_slide, &(d3_t){5,0,0} },
+		    { type_rot_way, &(struct rot_way){
+		      .l=LINE_Z,
+		      .deg_way={ .n=2, .vs=(double[]){0,360*2}, .ts=(double[]){4,4}, .ps=NULL, .dg=3} } },
+		    { type_copy, &(struct copy){ .n={2,1,1}, .init={-2,0,0}, .step={4,0,0} } },
+		    { type_end }
+		  }},
+		  .data = &(data_t){ type_cube } }};
+
 		data.type = type_arr;
 		data.p = (data_t[]){
 			*axyz,
 			*cross,
 			*cube, *cube3,
+			*cup,
 			{ type_end }
 		};
 	}