space plane
version 0.2

# Change these parameters to make another isosceles triangle.
param halfBase 3 range 1 5 step 0.1
param height 4 range 1 6 step 0.1
point A 0 height
point B (-halfBase) 0
point C halfBase 0
point M = midpoint(B, C)
segment AB A B
segment AC A C
segment BM B M
segment MC M C
segment AM A M

# Black strokes and point labels for a printed student paper.
style AB stroke #111111 width 2
style AC stroke #111111 width 2
style BM stroke #111111 width 2
style MC stroke #111111 width 2
style AM stroke #111111 width 2
style A stroke #111111 fill #111111 dotSize 0.7
style B stroke #111111 fill #111111 dotSize 0.7
style C stroke #111111 fill #111111 dotSize 0.7
style M stroke #111111 fill #111111 dotSize 0.7
label A text "A" offset 0.2 0.55
label B text "B" offset -0.7 -0.6
label C text "C" offset 0.3 -0.6
label M text "M" offset 0.2 -0.6
mark tick AB count 1
mark tick AC count 1
mark tick BM count 2
mark tick MC count 2

# These assertions check the givens; they do not add visual marks.
assert dist(A, B) == dist(A, C) tolerance 1e-6 note "AB = AC"
assert dist(B, M) == dist(M, C) tolerance 1e-6 note "M is the midpoint"

# Teacher version only: append `mark right B M A`.