These words are all around "gōngchéng", that is project in "English", however, the same phrase in different situations has different meanings. I just listed some of them and explain them simply. I hope it can help you to understand the complicated yet colourful Chinese language.

1. ān jū gōng chéng
    安 居    工      程

Urban housing project for low-income residents

Here 安 means to let people live peacefully and conveniently, 居 here refers to residents who are not rich; in Chinese we call them 低收入居民 (dī shōu rù jū mín).
工程 is the word we will use to mean the project is to build the house for low income residents.

2. dòu fǔ zhā gōng chéng
      豆   腐   渣    工      程

Low quality projects that do not meet requirements or standards

豆腐 (dòufu) is bean curd or tofu, which is soft and easy to break. 渣(zhā) means dregs or sediments, that is they are not useful. 豆 腐 渣 refers to things that are like broken bits, totally rubbish. 工程 means to build the housing. The phrase means the housing are too weak to live in. It is dangerous because it is a low quality building.

3. xī wàng gōng chéng
     希 望        工        程

The hope project to help children from rural areas or unfortunate families to proceed with their education.
希望 (xīwàng) means hope, 工程 (gōngchéng) doesn't mean housing but means the great plan.