  We demonstrate in this letter a unique approach for watching outside while
hiding in a carpet cloaking based on transformation optics. Unlike conventional
carpet cloaking, which screens all the incident electromagnetic waves, we break
the cloak and allow incident light get into the carpet. Hence outside
information is detected inside the cloak. To recover the invisible cloaking,
complementary techniques are applied in the broken space. Consequently, a
hiding-inside-and-watching-outside (HIWO) carpet cloak is sewed, which works as
a perfectly invisible cloaking and allows surveillance of the outside at the
same time. Our work provides a strategy for ideal cloak with "hiding" and
"watching" functions simultaneously.
