My point exactly. These tarps are an incredible source for zillions of improvizations, easy to setup and take off, and incredibly heavy duty! You can cut a piece and have no noticeable impact from that on your shelter, contrary to any tent (many folks above plan to cut something from the tent and still retain its bug/weeatherproofness properties after that, but even if you use only the rainfly for something unusual - you can quickly ruin its waterproofness really easy with the typical PVC/urethane coating used for that). Besides, the tent pictured is really not suitable for any serious shelter from elements, as that's the cheap Wnzel Alpine 3 person tent: http://www.amazon.com/dp/B002PAT60S even the rainfly on it is a joke

The FAK could be definitely essential if we know its content. The one pictured, is quite a good one actually (but not ideal, as Jacqui expecting): https://www.optomo.com.au/product/sports-first-aid-kit/ However, I would adjust my kit replacing the mirror with it. So my revised list would be:

Tarp, knife, FAK, flashlight.

A flashlight is better for the night signaling because you can use morse code to convey your message clearly and effortlessly any moment and to any direction (imagine that you heard a ship/plane/copter coming in the vicinity of the opposite to your shelter side of your densely "firewooded" island (tall trees), where you can run, but cannot bring your 3 piles of wood quickly). Also, with the signaling fire, you need to build and feed 3 of them (distress signal) in a wide enough row every night - that's a lot of resources and energy to spend (still doable, granted the island provides plenty of resources to replenish that energy daily).

By the way, I saw a lot of hype on preppers resources about the importance of having a glowstick, which being spinned on a cord should create a "highly visible glow ring" for signaling. However, from my astronomy (and thus light physics and visual perception) experience, a concentrated bright point is much more visible over a greater distance, especially compared to the barely visible glow produced by the chem.stick, dispersed over a large field of view (some may recall the laser beam test explained here a while ago supporting that as well). The wider motion of the light might play a role here, though, so if in doubt, I'd rather hold my >100 lumen flashlight with a long leafy branch in one hand and wave it around making sure it's well illuminated. Or I can illuminate in a SOS morse pattern a well visible from around tall tree instead. A green laser could work great for that as well, if you shake it in a fast "scanning" motion over the tree branches (had heard a loud "wow!" from the half a mile over the lake campground once, when played with my astronomy green laser that way at night, perhaps, thy thought it was an UFO landing ).

Another nice "flashlight on a rope" night signaling technique, I'm aware of, is great for the wide open horizon: attach it by the rear end to a 6-7' rope, make a knot (or a finger sized loop) at 2-3' and at the other end. Hold it over the shorter khot and swing the flashlight above the head, making sure it goes close to the horizontal plane, exactly 3 times, quickly switch to the end knot and swing 3 more times. Repeat until tired. That will create the well recognizable SOS beacon, efficiently visible to distant observers from every direction around you.