A good illustration of the Trinity comes from world-renowned scientist Dr. Henry Morris. He notes that the entire universe is trinitarian by design. The universe consists of three things: matter, space, and time. Take away any one of those three and the universe would cease to exist. But each one of those is itself a trinity.
Matter = mass + energy + motion
Space = length + height + breadth
Time = past + present + future
Thus the whole universe witnesses to the character of the God who made it (cf. Psalm 19:1).
Source: “God in Three Persons: A Doctrine We Barely Understand” by Dr. Ray Pritchard. Calvary Memorial Church, Oak Park, Illinois, 1997.