Coding on the Back of a Turtle Quiz

Answer: Move and rotate commands

The Logo turtle is controlled like you would control a small, simple robot (which is exactly what it was in the 1960s implementations). You can tell it to move forward or backwards, rotate right or left and raise or lower its pen (triggering whether the movement will draw a line or not).

Answer: The number 1

These commands are a simple sequence. You first move up 15 units to create a vertical line, then rotate 135 degrees to the left (so you point left and down) and move another 5 units in that direction. The pen is down, so you are actually drawing.

Answer: repeat 4 [forward 8 right 90]

If you're used to other languages, this takes getting used to. The "repeat" command is not a conditional loop with an "until" clause but essentially works like the "for" construct. You may note the similarity of all these commands - the keyword is immediately followed by an argument and there are no separators.

The interpreter recognizes your next command simply by the presence of a keyword.

Answer: Alternate moves and turns in tiny increments

The turtle has no memory of what it last did and doesn't even know where it is. It also can't do more than one thing at a time. Yet, you can create a reasonable circle by just drawing a polygon with very many sides. 360 is a good number, so we will do this:

repeat 360 [back 1 left 1]

I've drawn my circle walking backwards - it has the same effect as going forward, but it gives style points.

Answer: print

Just like in BASIC, the command to print text (originally on an actual printer, of course) is simply "print". You can print numbers or text; if you want to output text, you need to prefix it with a quote character, but there's no closing quote.

print "FunTrivia

is correct syntax and will send "FunTrivia" to your preferred output device.

If I want to print several words at a time, each one needs to have its own quote.

print "I "print "words

will result in the output "I print words"

Answer: to ask

Remember this is a language for children? "Dear computer: To ask, you need to do the following things" is just how a child would describe things. Here's what it looks like:

to ask
print "How "are "you
print "?
end

Answer: The colon (:)

Before you rush off to program with your new variables, keep in mind that Logo doesn't just assign things - the main way of using variables is as parameters. Using a variable, we can create a procedure that creates a polygon of any number of sides we want:

to polygon :sides
repeat :sides [forward 20 right 360/:sides]
end

Calling polygon 3 will draw a triangle and polygon 7 a nice regular heptagon. Did you notice that arithmetic works just like in other programming languages? Phew!

Answer: Pretty much everything you can think of

Technically, a Logo variable always holds a list (just as in Logo's ancestor, LISP), but a list can be pretty much anything you want. It can be a single number, a text, a sequence of multiple numbers and texts, even mixed (similar to an array), it can even be or contain a procedure.

Answer: first and butfirst

Again, the language chooses simple, child-friendly terms. You take the "first" item of the list and the rest is "butfirst", everything but the first item.

The LISP terms are a leftover from the very first implementation on a very obscure piece of hardware. "car" stands for "Contents of Address part of Register" and "cdr" is the acronym for "Contents of Decrement part of Register". I'll stick with first and butfirst, thanks!

Answer: A star

As written in the question, my procedure will only work for odd numbers; the geometry does not work out for even ones. I can fix that by extending the loop:

to star :lines
repeat :lines*2 [forward 100 left 180-180/:lines]
end

but this still has the small fault that even parameters will result in twice as many points as specified (star 4 gives 8 points). I'll leave further improvements to you :)