The previously discussed concept of what constitutes a monad - defined by number (including duration or ontological inertia), form, and beauty - is inaccurate in a very important way. That is, it depends on naive sense-perception when making a judgement of what is real, what is monadic (that which experiences). This is a very animalistic, ad hoc way of looking at things. Strictly speaking, we don't know what the bathmat is, other than the sense-product of the interaction of principles. Anything lacking a nervous system so appears to be an indeterminate thing. That is the ad hoc level of appraisal.
The higher level is the principled level, which is dominated exclusively by monads. We can call them principles, ideas, forms, or intentions, but monads will do. These comprise the higher animal life forms - anything with a nervous system - and the discoveries of principle such as Kepler's universal gravitation as the monad of the Solar System. And it is the function of science and art, in their investigative phases, to discover these monads, these actual substances of nature, which lurk beyond and behind the sense-impressions that we commonly and naively term "reality".
So we have two levels: sense experience, and cognitive experience. This means that no matter how much we love amoebae, we can't (yet) assert their reality as monads, but rather only as what appears to be an expression of the principles of organic matter.
How does beauty fit into all this? Isn't beauty compromised if we face, for example, a beautiful marble statue that we can't identify as a monad because it lacks a nervous system? Well, no. Beauty is a function of appearance. So we have this sensed monad, this statue, and it displays an image, the image (that which is represented) masters the matter (that which is representing), such that, ideally, the image completely obscures the material as material. So there, in the appearance, we have a monad, an idea, a principle of art, a form, a rational intention by the artist.
This idea can be copied, and in that sense the monad is non-local. Michelangelo's David can be copied and so reflect out into the universe, similar to how various viewers of the original work will reflect the idea of the statue into their minds. This does not make it more than one monad. Similarly, multiple people can "copy" the monad of the Solar System and yet that monad remains one thing.
In summary
1. Sense impressions show monads defined by
(a) Number
(b) Form
(c) Beauty
2. Cognitive discoveries show monads defined by principles, ascertained through solutions to ontological paradox
The overlap is that creatures with nervous systems are monads at both levels. Examples of each would be:
Sense Impression Monads
minerals
unicellular life
furniture
infrastructure
Cognitive Monads
animal life
human beings
scientific principles (e.g., principle of the pulley)
artistic principles (e.g., Mozart's Requiem)