md`# ${sparkline([ [Math.abs(Math.sin(now/1000 % 1000))*10+10, 10* Math.abs(Math.sin(now/1000 % 1000))*10], [Math.abs(Math.cos(now/1000 % 1000))*10 + 20, 5* Math.abs(Math.cos(now/1000 % 1000))*10+ 20], intervals_union([Math.abs(Math.sin(now/1000 % 1000))*10+10, 10* Math.abs(Math.sin(now/1000 % 1000))*10], [Math.abs(Math.cos(now/1000 % 1000))*10 + 20, 5* Math.abs(Math.cos(now/1000 % 1000))*10+ 20]) ], 100, 15, null, [0, 200])} Altitude ${sparkline(normalizeIntervals([[Math.abs(Math.sin(now/1000 % 1000))*10+10, 10* Math.abs(Math.sin(now/1000 % 1000))*10], [Math.abs(Math.cos(now/1000 % 1000))*10 + 20, 5* Math.abs(Math.cos(now/1000 % 1000))*10+ 20], [Math.abs(Math.tan(now/1000 % 1000))*20 + 10, 3* Math.abs(Math.tan(now/1000 % 1000))*10+ 20]]))} *An implementation of [Allen Temporal Algebra](https://en.wikipedia.org/wiki/Allen%27s_interval_algebra) to deal with interval data.*

import { al } from '@romsson/altitude'

The 13 Allen relations as published in the [original paper](https://cse.unl.edu/~choueiry/Documents/Allen-CACM1983.pdf) are as follows:

${renderIntervals(sample_precede, 88)}

X **precedes** Y
Y is **preceded** by X

${renderIntervals(sample_meet, 88)}

X **meets** Y
Y is **met** by X

${renderIntervals(sample_overlap, 88)}

X **overlaps** Y
Y is **overlapped** by X

${renderIntervals(sample_start, 88)}

X **starts** Y
Y is **started** by X

${renderIntervals(sample_during, 88)}

X **during** Y
Y is **contains** by X

${renderIntervals(sample_end, 88)}

X **finished** Y
Y is **finished** by X

${renderIntervals(sample_equal, 88)}

X is **equal** to Y