tupel.js

var input = ['p1', 'p2', 'p3', 'p4', 'p5', 'p6']
var output = [];
var counter = 0;

for(var i = 0; i <= input.length-1; i++) {
    var tupel = [];
    
    if(counter == 0) {
        tupel.push(input[i])
        counter++;
    }

    if(i == (counter - 1)) {
        tupel.push(input[i+1])
        output.push(tupel)
    }

    if(counter < i) {
        tupel = [];
        tupel.push(input[counter])
        tupel.push(input[i])
        output.push(tupel)
        counter++;
    }
}

console.log(output)