Stephen Wolfram's Rule 30 output in Bash, generated (mostly) via ChatGPT4

rule_30.bash

#!/usr/bin/env bash

# Get the terminal width
width=$(tput cols)

# Set number of output lines
LINES=${LINES:-10000}

# Initialize the first row with a single block character in the middle
row=$(printf "%-$((width / 2))s" " ")
row="${row}█${row}"
row=${row::width}

# Rule 30 in Bash!
rule30() {
    local prev="$1"
    local cur="$2"
    local next="$3"

    if [[ ( $prev == "█" && $cur == "█" && $next == "█" ) || 
          ( $prev == "█" && $cur == "█" && $next == " " ) || 
          ( $prev == "█" && $cur == " " && $next == "█" ) || 
          ( $prev == " " && $cur == " " && $next == " " ) ]]; then
        echo " "
    else
        echo "█"
    fi
}

# Print the cellular automaton
echo "$row"
for _ in $(seq $((LINES - 1))); do
    new_row=""
    for i in $(seq 0 $((width - 1))); do
        prev=${row:$(( (i - 1 + width) % width )):1}
        cur=${row:$i:1}
        next=${row:$(( (i + 1) % width )):1}
        new_row+=$(rule30 "$prev" "$cur" "$next")
    done
    row="$new_row"
    echo "$row"
done