The amazing Amira Hass has brought out information from Gaza, about what Israel allows into the blockaded territory. From Haaretz:
The few items merchants are allowed to trade in are
divided into three categories: food, medicine and detergent. Everything
else is forbidden – including building materials (which are necessary
to rehabilitate Gaza's ruins and rebuild its infrastructure), electric
appliances such as refrigerators and washing machines, spare machine
and car parts, fabrics, threads, needles, light bulbs, candles,
matches, books, musical instruments, crayons, clothing, shoes,
mattresses, sheets, blankets, cutlery, crockery, cups, glasses and
animals. Many of the banned products are imported through the tunnels
and can be found in Gaza's markets.
(Thanks to Eva Smagacz.)