SK Combinator Expression Analysis

Input a valid SK combinator expression or use the random expression above.

Expression:
s[s][s[s[k]]][k[s[k]][s[s[k]]]][s][k[k][s[k]][s][s][s[s][s][k[k]]][k[k[k]]]]
Visualisation:
Initial state and first 5 steps of evaluation:
The nth row of the image represents the nth step of evaluation of the combinator.
Graph of Evaluated Expression Lengths:
As the combinator is evaluated, its length changes. This graph plots length of combinator against number of steps of evaluation.
Statistical Analysis of Halting Time:
This combinator has 26 leaves. This combinator falls within the 87th percentile of a random sample of 1000 combinators with leaf size 26, halting after 11 steps - on average, 87.9% of combinators from this sample halt before this one. A graph demonstrating this follows:
Machine Learning Analysis of Halting:
A machine learning model (using logistic regression) has been trained on a sample of 1456 rasterised images of the first 5 steps of random SK combinator expressions with varying leaf lengths, achieving 87.7% accuracy when classifying a test set of 1454 random SK combinator expressions as halting or non halting (before 40 steps).
This particular expression, which halts after 11 step(s), is classified as having a Indeterminate% probability of halting, and a Indeterminate% probability of not halting (before 40 steps).
Evaluated expression:
Halted in 10 step(s)
0s[s][s[s[k]]][k[s[k]][s[s[k]]]][s][k[k][s[k]][s][s][s[s][s][k[k]]][k[k[k]]]]
1s[k[s[k]][s[s[k]]]][s[s[k]][k[s[k]][s[s[k]]]]][s][k[s][s][s[k[k]][s[k[k]]]][k[k[k]]]]
2k[s[k]][s[s[k]]][s][s[s[k]][k[s[k]][s[s[k]]]][s]][s[s[k[k]][s[k[k]]]][k[k[k]]]]
3s[k][s][s[k][s][k[s[k]][s[s[k]]][s]]][s[s[k[k]][s[k[k]]]][k[k[k]]]]
4k[s[k][s][k[s[k]][s[s[k]]][s]]][s[s[k][s][k[s[k]][s[s[k]]][s]]]][s[s[k[k]][s[k[k]]]][k[k[k]]]]
5s[k][s][k[s[k]][s[s[k]]][s]][s[s[k[k]][s[k[k]]]][k[k[k]]]]
6k[k[s[k]][s[s[k]]][s]][s[k[s[k]][s[s[k]]][s]]][s[s[k[k]][s[k[k]]]][k[k[k]]]]
7k[s[k]][s[s[k]]][s][s[s[k[k]][s[k[k]]]][k[k[k]]]]
8s[k][s][s[s[k[k]][s[k[k]]]][k[k[k]]]]
9k[s[s[k[k]][s[k[k]]]][k[k[k]]]][s[s[s[k[k]][s[k[k]]]][k[k[k]]]]]
10s[s[k[k]][s[k[k]]]][k[k[k]]]