For small image repeated/tiled, use colorWithPatternImage

For large full-size image, use UIImageView

What? Functions you can pass as arguments to other functions. Such as map, filter, reduce, flatMap.

• map – operate on each element in the collection (then return a new collection).
• filter – return a subset of the collection that satisfies some condition. 
• reduce – combine and return a single value. 
• flatMap – flatten a collection of collections into a collection. 

• cell creation
• transparency
• gradient
• shadow
• off-screen drawing
• image scaling
• row height calculation
• api call
• data transformation
• deep subviews