Printing criss cross of two strings
JavaScript (ES6), 51 bytes
f=([G,...O],[L,...F])=&gt;O[0]?F[0]+G+L+O[0]+f(O,F):''



f=([G,...O],[L,...F])=&gt;O[0]?F[0]+G+L+O[0]+f(O,F):''

console.log(f("Truck", "Tower"))