Here are a series of systems I diagrammed in the early 2000s using the Energy Systems Language. Rendering of all diagrams was done by me (e.g. not a software package).
Energy systems language is a versatile approach to modeling complex systems. Given a system boundary and a series of inputs, the goal is to model the aggregate flow and processing of energy within that system. "Energy" is defined according to the concept of emergy (also called embodied energy) , which more completely defines the value of objects and processes than do other forms of currency (gold, meters, money see ).
Emergy is also related to a concept called transformity , or how energy gets transformed as it does work (e.g. passed through a set of trophic relationships). This form of energy conversion , denoted by the exponential scale along the side of the system boundaries, has three outcomes. These are: conversion to a higher form of energy, waste (lines that cross the lower boundary of the system), and information (can either be embodied in a higher form of energy or as a feedback).
While these types of diagrams are generally used for ecological and social systems, then can also be used to characrerize biological  and technological complexity. The examples below are some of these more "unconventional" applications of the systems language.
1) The hardware and information associated with a traditional computer. Click to enlarge.
2) The physiology, environment, and information associated with natural language. Click to enlarge.
3) The hardware and information associated with a computer virus. Click to enlarge.
4) The information and operations associated with cultural transmission within and between individuals . Click to enlarge.
 as you might imagine, it is an imperfect science. For more information, please see the following review: Hau, J.L. and Bakshi, B.R. Promise and Problems of Emergy Analysis. CiteSeerX, 10.1.1.115.7352.
 Odum, H.T. (1996). Environmental Accounting: emergy and environmental decision making. Wiley, New York.
 Brown, M.T. and Ulgiati, S. (2004). Energy quality, emergy, and transformity: H.T. Odum’s contributions to quantifying and understanding systems. Ecological Modeling, 78(1-2), 201-213.
 Tonon, S., Brown, M.T., Luchic, F., Mirandola, A., Stoppato, A., and Ulgiati, S. (2006). An integrated assessment of energy conversion processes by means of thermodynamic, economic and environmental parameters. Energy, 31(1), 149-163.
 Jorgensen, S.E., Odum, H.T., and Brown, M.T. (2004). Emergy and exergy stored in genetic information. Ecological Modeling, 78(1-2), 11-16.
 in this diagram, I have incorporated elements of information processing (e.g. choice generator) that fall outside the traditional applications of these models.