Punch

Punch is a short-ranged spell which, in the hands of a competent mage, is capable of significantly denting steel plate armor.
Hana's Law: Construction energy equal, projections impart more force on impact if moving at higher velocities. At the same time, the energy cost of sustaining a projection increases exponentially as its speed increases. However, it's not possible for a mage to simply "put more energy" into a projection. Punch optimizes damage by maximizing the effect of Hana's Law given a set amount of energy, sacrificing range and casting speed to do so.
It's traditionally the first 'serious' spell taught to initiates, as it introduces them to key concepts, both magical and mundane. One of the first spells to be truly standardized, Punch was created not long after the founding of Hauntfall and the initiate-mage-archmage system. Though there are more effective ways to achieve its effects, it remains a beginner's staple largely due to its simplicity and extensive documentation, not to mention the weight of tradition.
The spell is a trial by fire in the use of systematic projection, which is an approach towards creating light constructs key to building more complex works. Initiates are usually first taught instinctive projection, because the first hurdle is making projection happen at all (see: Light Knives). However, when it comes to more complex, multi-stage works, one cannot simply 'eyeball it'. Systematic projection focuses on process rather than result, and can be vaguely thought of as passing transformation matrices to one's soul, rather than attempting to adjust it by feel. It's slower due to the added layer of abstraction, and requires more memorization/knowledge, but provides a much more stable foundation: important when you've got, say, a continuously-running spell that requires precise input to stay stable.
More goes into this than merely the capability to project light: math and physics are key components to truly understanding what's happening. All systematic projection at the very least requires knowledge of coordinate systems. Punch itself is essentially a series of levers etc.
Overall, it's the most basic systematic spell, but it is a spell.