// ... // store the current timenow => time t1;  //value to duration0.5::second => dur d; <<<"one">>>;//now waits for that duration d => now;<<<"two">>>; //define new durationd * 4.0 => dur four_d;  //wait again. four_d => now;<<<"three">>>; now => time t2; t2 - t1 => dur span;<<<"total">>>;<<<span>>>;<<<"relative">>>;<<<span / d>>>;