export function wordFactorial(words: string[]): string[] {
  const combinations: string[] = [];
  for (let i = 0; i < words.length; i++) {
    let inner = '';
    for (let ii = i; ii < words.length; ii++) {
      inner += (ii > i ? ' ' : '') + words[ii];
      combinations.push(inner);
    }
  }
  return combinations;
}