Trains, in a way, and the key to 18 of this puzzle's black squares. (Ones that begin with the keyword are asterisked. The others are for you to discover.)

Question:

Answer:

SHADOWBOXES

Length:

Similar Crossword Questions:

Like aleph in the central black squares of this puzzle's grid
Complete set of 12 shapes formed by this puzzle's black squares
Web concerns ... and based on six familiar names hidden in rows 1, 4, 12 and 15 of this puzzle grid, what the black squares in those rows symbolize
On hold ... or what the seven rows of black squares in this puzzle's grid spell in Morse code
Row of black squares preceding or following six puzzle answers, thereby completing them
How this puzzle's black squares are arranged
What the answers to asterisked clues begin with
Secret get-together, or what occurs literally in each of this puzzle's circled squares
Puzzle based on Latin Squares
Fans of black-and-white squares
Like the Oscars ... or the answers to this puzzle's seven asterisked clues?
Geographical features ... or what the circled squares in this puzzle represent
What the three sets of circled squares in this puzzle represent
Lower septet of black squares in this grid, typographically
Phenomenon observed in receding galaxies ... and in the answers to this puzzle's asterisked clues?
What spouse does, step 4 [hint: look at the black squares of the grid]
Term for each of the 15 asterisked theme answers in this puzzle
Number of times this puzzle's theme word appears diagonally in the grid (to complete the puzzle, shade those words plus the Down answers that begin where they meet)
Company "sorted" in this puzzle's circled squares
Angle irons graphically represented by four sets of black squares in this grid, and by letter formations starting in the four longest answers
This puzzle's theme, whose first notes are indicated by shaded squares
Your role in this puzzle [the asterisked clues will help you crack the case]
What the highlighted squares in this puzzle represent
Visual representation of an item associated with the answers to the asterisked clues in this puzzle
Item with features that begin this puzzle's four longest answers