The president （主语）tweeted out （谓语动词）an illustration （宾语）of a very pointy, very high metal fence（illustration 的定语） which he called “our Steel Slat Barrier which is totally effective while at the same time beautiful!”（fence 的定语从句）

再分析 which he called “our Steel Slat Barrier which is totally effective while at the same time beautiful!”：

1. which 是called 的宾语。整个引号部分是called 的宾补。

2. 引号部分：our Steel Slat Barrier 是宾补的中心词，which is totally effective while at the same time beautiful是其定语从句。