You can emit light and still be in a greater shadow, otherwise everybody with a torch would be immune to the tower.
As long as its light can't compete with the sun it can still be in shadow. It's just the night-time usage that can be shut off with a bright enough campfire.
My assumptions were "learning a Moderately Complicated spell at our level of Magic has a base DC of 60, reduced by 10 for College instruction, for Fiendishly Complex add 10, and for it being Partially Known we get +10 on the roll." I had actually forgotten, when I did the earlier calculation, that Illusion was FC instead of MC, but that makes the math super easy: odds of failure for a Moderately Complicated at college with no prior knowledge is .23 (we have 26 learning and succeed if we hit the target number), odds of failure for a FC with some study is .23 as well (26 learning + 10 partial against DC 60), so .23 cubed is 1.2% odds of failing to learn any of the three spells that cover our ass, which is a lot better than our odds of failure when we're betting it all on Shroud of Invisibility.
@BoneyM Point of clarification with regards to Burning Shadows: How much of a light source would be required to make it so you were no longer being burnt:
In comparison to sunlight a regular torch doesn't dispel the shadow IMO - you're still very clearly darker than you would be in sunlight.
The Red and Blue supplementary towers don't follow the same rules as the Penthouse towers for our personal use. Someone asked if we could spend a Penthouse action to build one AP-free and BoneyM said no, so they don't benefit from Penthouse action economy, but they also don't suffer from its limitations. Since both those options are new, Boney would have said if we could only do one.
My belief is that if we learned it at home, the +20 from the Tower of Dawn and Dusk would more than counteract the +10 DC from college instruction, but that gives us odds of failure at around 13%, which I would have been okay with but not comfortable about it. Being able to try for all three at the same time is really useful from a cover-our-ass perspective, and super in character for Mathilde, who has a habit of just swinging her influence around when she is frustrated by not being able to get something because luck is against her (remember Wizard Chic?).
It seems... boorish of us. Arriviste. Yes, it might be action-efficient, for us.
It is legal. We have one free improvement, without expending any actions. We could have always just make effort and build multiple rooms/towers. It would just cut into Mathilde's time. Here, we are expending action. It is also part of official task beside.
It's an Ice Dragon. Despite what the thread appears to have decided, that neither a) automatically means it can use magic and b) doesn't automatically mean it's old enough to be the equivalent of an Emperor Dragon. It could 'just' be an Ice Dragon that's a couple centuries old. It'll almost certainly be hard to defeat, but an Emperor Dragon is the sort of thing that kills armies.
