what's the algorithm

During the first lecture a little bit make me confuse about 'what is the algorithm?'

So I check some website, try to find out the meaning of it.

It is kind of mathematics problem.

E.g. Data Flow Diagram. it is used for see the processes and what the data is transferred between different functions. The process or function is expressed as some shape and link between each process shows which one passes to other one.

Here are some  some picture might be correctly explained the this answer. The anti-aliased gray scale images. Distance transform and volute. A visual display designed to make it distinctive and memorable.

Image from:

http://www.scienceprog.com/how-to-describe-embedded-software-design-using-diagrams-and-pseudo-code/

http://www.vizworld.com/2009/10/antialiased-euclidian-distance-transform/

www.google.com