External anatomy and references.
Synthagen have a rounded face that is completely covered in a monitor, the center of which extends to a snout. Beneath this snout is a mouth and above it are eyes. All of the facial features of a synthagen are drawn on the monitor, usually in green or blue if available but colors often vary based on mood. Above this monitor is a small metal band which contains a headlamp that the synthagen can turn on to see better in the dark. Above this band are its ears, which are half cones and point upwards, with an appearance similar to a fox. Below their visor is a short neck. Two arms extend from synthagen’s shoulders below their neck. Their arms are very human-like, with joints at their elbows and wrists, as well as 4 fingers and a thumb for grasping objects. Their upper chest holds all of the synthagen’s external cable plugs, which are only visible or accessible at the synthagen’s choice and even then are often buried deep in fluff. At their midsection, which is slightly less wide than their shoulders, the largest synthagen have two additional arms identical in appearance to the ones at their shoulders.
At their waist, normally hidden by skin and kept internally, are any sexual organs, synthagen can change their sex over a period of about 24 hours. Non-micro synthagen support fertility which allows them to give birth internally, lay eggs, or impregnate others. Synthagen cannot create new synthagen this way, only other animals1. So, for example, a human and synthagen could give birth to a new human, or even a human/animal hybrid, but not a human/synthagen hybrid or synthagen.
For micro and normal synthagen, their tail is also at their waist behind their body. The tail is fully prehensile and is the only limb that can have two modules, one to determine its shape (which defaults as short and thick, but can also be long and thin like a monkey, or even fin shaped for better swimming). The other is a regular module slot that can hold all the same modules as an arm or leg. Below the waist are two legs, which are also quite human like, being bendable at their knees. Synthagen legs are somewhat thicker than their arms and also somewhat longer. They end in 5 short toes unless a module was installed to, for example, replace them with claws.
(TBD, get a drawing for final draft)
[What to do here]
Just behind a synthagen’s visor is its mouth, which is the first part of a fully self-contained digestive system. This includes a grain or carbon-tropic system which processes grains or food without creating any waste. Its entire digestive system only extends down to its upper chest. Excess nitrogen, and carbon dioxide from digestion is excreted directly into the lungs which are on both sides of a synthagen’s upper chest, synthagen produce no solid or liquid waste. Connected to the lungs is the circulatory system, a network of chitin hemolymph pipes which, thanks to two small pumps, carry both nutrients and oxygen. These pipes are strong and fairly rigid and thus also serve as the skeletal system of the synthagen, and as a liquid cooled heat sink for the brain. Insulated metal wires run alongside these pipes adding rigidity and providing electrical power to the synthagen.
At the lower chest region, held in place by chitin, is the brain of a synthagen. Depending on the creature’s size, a mini-itx, micro-atx, or atx motherboard is fitted. Soldered on to it are the central processing unit, the same model used in Nexus-6 replicants, as well as some memory and solid state storage, the sizes of which are not defined in the specification because even the cheapest Nexus-6 boards come with sufficient amounts of both. The motherboard connects to hundreds of sensors around the synthagen’s body, which give it the ability to perceive the world around it. Below these core components are several interconnect slots, which can be fitted with 4, 5, or 6 modules for the different sized synthagen. Below this, in the chest region, are the 5 volt batteries. At least one needs to be installed at all times to keep them alive.
At the base of each limb is a module slot with the M.2 form factor. The tail if present, has two of these module slots. The limbs have motors2 at their base and at each joint, allowing a full range of motion. The tail has a tiny motor every few centimeters, allowing for it to be controlled in complex ways. Besides these, the limbs and tail are mostly internally hollow, making them incredibly dexterous, and capable of performing incredible sleight of hand tricks. Despite this hollowness, just below the surface of the synthagen’s skin is a spongy material that makes them quite soft on the outside.
(TODO: insert drawings of internals. Maybe get a drawing of the external and create a cutaway in Krita)