Photo:.Supply and demand. The supplier and the demander come to an (implicit) agreement, on things like price, quality, delivery time, etc. Supplier 1, 2, 3 and 4 can be different companies. In larger companies the suppliers can be internal. Supply and demand can be stacked like in these similar images:1, 3, 4.
CBS Eyes on the World with John Batchelor CBS Audio Network @Batchelorshow
Supply Chain Inflation & What is to be done? @VeroDeRugy @Mercatus GLXXG