Make a GIANT greeting card out of a big cardboard box, (such as the type used to pack a refrigerator).
用一个大纸板箱做一张巨型贺卡，(例如用来包装冰箱的纸板箱)。
2
A black card is just a regular cardboard paper. The key point is the color black. Black absorbs light. Therefore, the camera will not capture the black card.