Ænigmatic Addenda

Guest Constructors Revisit the Adalogical Ænigmas

Welcome, gentle solver!
Seemingly from the day I first began my Adalogical Ænigmas series, kind patrons have expressed to me both their satisfaction with my efforts and a measure of what we might call disappointment: that, having derived the necessary deductive techniques for solving an ænigma, they had but a single instance upon which to practice their hard-won skills.
During the preparation for our fund-raising campaign (in support of my first collection of ænigmas), my associate Mr Curtis and I realised that we could, at last, grant the wishes of those solvers! The solution was to employ the talents of our wide circle of ænigmatological acquaintances: we could, with the financial assistance of our wonderful supporters, commission guest constructors to revisit some of the types of conundra that I had previously introduced.
At the midpoint of each month, funding permitting, we shall present a fresh Ænigmatic Addendum. The initial half dozen such works were paid for by our fine Kickstarter backers. Subsequent entries in the series are made possible through the generous support of our patrons on Patreon: for every $10 exceeding $150 that we receive in monthly patronage, we place one imaginary token into an equally imaginary account. Each time that said account accumulates a total of 30 tokens, we are privileged to commission one further Ænigmatic Addendum.
At present, we have commissioned Addenda through #6, and our running account boasts 22 of the 30 tokens necessary for adding #7 to the series.
As with the entries in my own Adalogical Ænigmas series, and in addition to its value as intellectual stimulation, each Addendum also serves as a contest! If you solve an Addendum within one month of its publication, you could win a free physical puzzle from among the wares offered by Pavel's Puzzles!
What follows is a catalogue of all of the Addenda yet made available to the solving public. Each puzzle image links to a page concerning that Addendum, including a copy of the Addendum itself.
With sincere hopes for your imminent befuddlement (and eventual enlightenment),
#2: April, 2017 (by Mr Grant Fikes, revisiting Ænigma #10)
#1: March, 2017 (by Mr David Millar, revisiting Ænigma #17)