It was also popular in the Shards of Alara block to see green, white, and blue Angels from the Shard of Bant. Also, in the Alara Reborn set, Filigree Angel was a white and blue artifact creature. The most known Angel in Magic is Akroma, Angel of Wrath. Released in the Onslaught expansion, Akroma was created by master illusionist Ixidor to fight Phage the Untouchable and the Cabal.
Deadlocks are sometimes called a deadly embrace. Deadlock is a condition that can occur on any system with multiple threads, not just on a relational database management system, and can occur for resources other than locks on database objects. For example, a thread in a multithreaded operating system might acquire one or more resources, such as blocks of memory.
Dead, in the sense of lifeless, is so commonly used that we tend to ignore its other meanings. The meaning that's relevant here is exact or precise. This is demonstrated in many phrases; 'dead shot', 'dead centre', 'dead heat', etc. So, 'dead ringer' is literally the same as 'exact duplicate'. It first came into use soon after the word ringer itself, in the US at the end of the 19th century.