Complete set of 12 shapes formed by this puzzle's black squares

Question:

Answer:

PENTOMINOES

Length:

Similar Crossword Questions:

Row of black squares preceding or following six puzzle answers, thereby completing them
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.)
How this puzzle's black squares are arranged
On hold ... or what the seven rows of black squares in this puzzle's grid spell in Morse code
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
Like aleph in the central black squares of this puzzle's grid
The 2x2 black square near the middle of this puzzle's grid, e.g., which is part of eight answers
What you're doing as you complete this puzzle
Fills, as black squares
Alice Walker novel ... or a hint to 12 squares in this puzzle
What's been deposited in four squares of this puzzle, expressed both by name and by symbol
"Hmmmmm ..." [as hinted at by the three groups of black squares in the middle of the grid]
TREASURE HUNT STEP 2 (include black squares)
Hint to filling in four squares in this puzzle
Angle irons graphically represented by four sets of black squares in this grid, and by letter formations starting in the four longest answers
Puzzle based on Latin Squares
Drink cooler ... or a hint to six squares in this puzzle's answer
Question asked by a customs officer or a kid on Christmas ... with a hint to this puzzle's circled squares
Higher pair of black squares in this grid, typographically
Common interface that is a model for several squares in this puzzle
What's revealed by connecting the special squares in this puzzle in order
"Apt" geographical element needed to complete the answers to 10 of this puzzle's clues
The word, as suggested by the saying formed by the ends of this puzzle's four longest answers
Type of gear on which the letters in this puzzle's nine theme squares are arrayed
What spouse does, step 4 [hint: look at the black squares of the grid]