# complexity #Pasted Gall's Law is a [rule of thumb](https://en.wikipedia.org/wiki/Rule_of_thumb "Rule of thumb") for [systems design](https://en.wikipedia.org/wiki/Systems_design "Systems design") from Gall's book _Systemantics: How Systems Really Work and How They Fail_. It states: > A complex system that works is invariably found to have evolved from a simple system that worked. A complex system designed from scratch never works and cannot be patched up to make it work. You have to start over with a working simple system.[[9]](https://en.wikipedia.org/wiki/John_Gall_(author)#cite_note-9) # Make deadlines for projects as short as possible There is an interplay between [[Parkinson's Law]] and [[Galls Law|Gall's Law]]. Teams will build solutions to the complexity level that is available in a time allotment. The implication is that if the deadline is not constrained to the simplest solution that will work, not only will the deadline be at risk, the success of the outcome will be at risk. This is one of the reasons sprints are effective in the [[Agile]] [[Development Process]].