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+++ b/day24.txt	Fri Jan 05 11:42:13 2024 +0000
@@ -0,0 +1,59 @@
+--- Day 24: Never Tell Me The Odds ---
+
+A set of objects have positions and velocities in 3D space, noted as `x, y, z @ Δx, Δy, Δz`, e.g.
+
+19, 13, 30 @ -2,  1, -2
+18, 19, 22 @ -1, -1, -2
+20, 25, 34 @ -2, -2, -4
+12, 31, 28 @ -1, -2, -1
+20, 19, 15 @  1, -5, -3
+
+Ignoring the Z axis, which objects will intersect _in future_ within a given bounding box.
+
+For example, with the box 7,7 to 27,27 and the objects above:
+
+Object A: 19, 13, 30 @ -2, 1, -2
+Object B: 18, 19, 22 @ -1, -1, -2
+Objects' paths will cross inside the test area (at x=14.333, y=15.333).
+
+Object A: 19, 13, 30 @ -2, 1, -2
+Object B: 20, 25, 34 @ -2, -2, -4
+Objects' paths will cross inside the test area (at x=11.667, y=16.667).
+
+Object A: 19, 13, 30 @ -2, 1, -2
+Object B: 12, 31, 28 @ -1, -2, -1
+Objects' paths will cross outside the test area (at x=6.2, y=19.4).
+
+Object A: 19, 13, 30 @ -2, 1, -2
+Object B: 20, 19, 15 @ 1, -5, -3
+Objects' paths crossed in the past for Object A.
+
+Object A: 18, 19, 22 @ -1, -1, -2
+Object B: 20, 25, 34 @ -2, -2, -4
+Objects' paths are parallel; they never intersect.
+
+Object A: 18, 19, 22 @ -1, -1, -2
+Object B: 12, 31, 28 @ -1, -2, -1
+Objects' paths will cross outside the test area (at x=-6, y=-5).
+
+Object A: 18, 19, 22 @ -1, -1, -2
+Object B: 20, 19, 15 @ 1, -5, -3
+Objects' paths crossed in the past for both Objects.
+
+Object A: 20, 25, 34 @ -2, -2, -4
+Object B: 12, 31, 28 @ -1, -2, -1
+Objects' paths will cross outside the test area (at x=-2, y=3).
+
+Object A: 20, 25, 34 @ -2, -2, -4
+Object B: 20, 19, 15 @ 1, -5, -3
+Objects' paths crossed in the past for Object B.
+
+Object A: 12, 31, 28 @ -1, -2, -1
+Object B: 20, 19, 15 @ 1, -5, -3
+Objects' paths crossed in the past for both Objects.
+
+
+
+Look for future intersections that happen with an X and Y position each at least 200000000000000 and at most 400000000000000. Disregard the Z axis entirely.
+
+Note: Some objects are moving upwards.
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