user1521: I am playing around with this Tinycircuits 16 LED board and I can figure out how to persistently light two LEDs at the same time. The page comes with an example that i can modify but I can only do 1 at a time 
How do I light more than one LED at a time?
/*
TinyDuino Edge LED Demo

April 9 2014, by Ben Rose

This example code is in the public domain.

http://www.tiny-circuits.com

*/

void setup()
{
  LedOn(0);//Pass a zero to turn all LEDs off
}

void loop()
{
  for(int i=1;i<16;i++){
    LedOn(i);
    delay(20);
  };
  for(int i=16;i>1;i--){
    LedOn(i);
    delay(20);
  };
}

void LedOn(int ledNum)
{
  for(int i=5;i<10;i++){
    pinMode(i, INPUT);
    digitalWrite(i, LOW);
  };
  if(ledNum<1 || ledNum>16) return;
  char highpin[16]={5,6,5,7,6,7,6,8,5,8,8,7,9,7,9,8};
  char lowpin[16]= {6,5,7,5,7,6,8,6,8,5,7,8,7,9,8,9};
  ledNum--;
  digitalWrite(highpin[ledNum],HIGH);
  digitalWrite(lowpin[ledNum],LOW);
  pinMode(highpin[ledNum],OUTPUT);
  pinMode(lowpin[ledNum],OUTPUT);
}


user-1: 
This is your circuit.
I think you can take it from here by looking at the diagram, but please note that e.g. 1 0 0 0 0 will light up 3 and 1, so be careful.
To show more than one, turn on multiple LEDs in rapid succession. It will give the effect that more than one are on. This is known as multiplexing.
Update:
After Googling around, I understood it better. I also wrote this code.
int IO1 = 50;
int IO2 = 48;
int IO3 = 46;
int IO4 = 44;
int IO5 = 41;
int del = 1000;

void setup() {

  pinMode(IO1, INPUT);
  pinMode(IO2, INPUT);
  pinMode(IO3, INPUT);
  pinMode(IO4, INPUT);
  pinMode(IO5, INPUT);
  Serial.begin(9600);
}

// the loop routine runs over and over again forever:
void loop() {
    displayLED(1);
    delay(del);
    displayLED(2);
    delay(del);
    displayLED(3);
    delay(del);
    displayLED(4);
    delay(del);
    displayLED(5);
    delay(del);
    displayLED(6);
    delay(del);
    displayLED(7);
    delay(del);
    displayLED(8);
    delay(del);
    displayLED(9);
    delay(del);
    displayLED(10);
    delay(del);
    displayLED(11);
    delay(del);
    displayLED(12);
    delay(del);
    displayLED(13);
    delay(del);
    displayLED(14);
    delay(del);
    displayLED(15);
    delay(del);
    displayLED(16);
    delay(del);// light up LEDS 1, 2 and 3.
}

void displayLED(int a){
    clear();
    if (a == 1){o(1); o(2); h(1); l(2); Serial.println('1');}
    if (a == 2){o(1); o(2); l(1); h(2); Serial.println('2');}
    if (a == 3){o(1); o(3); h(1); l(3); Serial.println('3');}
    if (a == 4){o(1); o(3); l(1); h(3); Serial.println('4');}
    if (a == 5){o(2); o(3); h(2); l(3); Serial.println('5');}
    if (a == 6){o(2); o(3); l(2); h(3); Serial.println('6');}
    if (a == 7){o(2); o(4); h(2); l(4); Serial.println('7');}
    if (a == 8){o(2); o(4); l(2); h(4); Serial.println('8');}
    if (a == 9){o(1); o(4); h(1); l(4); Serial.println('9');}
    if (a == 10){o(1); o(4); l(1); h(4); Serial.println(10);}
    if (a == 11){o(3); o(4); l(3); h(4); Serial.println(11);}
    if (a == 12){o(3); o(4); h(3); l(4); Serial.println(a);}
    if (a == 13){o(3); o(5); l(3); h(5); Serial.println(a);}
    if (a == 14){o(3); o(5); h(3); l(5); Serial.println(a);}
    if (a == 15){o(4); o(5); l(4); h(5); Serial.println(a);}
    if (a == 16){o(4); o(5); h(4); l(5); Serial.println(a);}

}

void clear(){pinMode(IO1, INPUT);
  pinMode(IO2, INPUT);
  pinMode(IO3, INPUT);
  pinMode(IO4, INPUT);
  pinMode(IO5, INPUT);}

void o(int o){
    if (o == 1){pinMode(IO1, OUTPUT);}
    if (o == 2){pinMode(IO2, OUTPUT);}
    if (o == 3){pinMode(IO3, OUTPUT);}
    if (o == 4){pinMode(IO4, OUTPUT);}
    if (o == 5){pinMode(IO5, OUTPUT);}
}

void h(int l){
    if (l == 1){digitalWrite(IO1, HIGH);}
    if (l == 2){digitalWrite(IO2, HIGH);}
    if (l == 3){digitalWrite(IO3, HIGH);}
    if (l == 4){digitalWrite(IO4, HIGH);}
    if (l == 5){digitalWrite(IO5, HIGH);}
}

void l(int h){
    if (h == 1){digitalWrite(IO1, LOW);}
    if (h == 2){digitalWrite(IO2, LOW);}
    if (h == 3){digitalWrite(IO3, LOW);}
    if (h == 4){digitalWrite(IO4, LOW);}
    if (h == 5){digitalWrite(IO5, LOW);}
}


1521: <p>I am playing around with this Tinycircuits <a href="https://www.tiny-circuits.com/tiny-shield-16-edge-led.html" rel="nofollow">16 LED board</a> and I can figure out how to persistently light two LEDs at the same time. The page comes with an example that i can modify but I can only do 1 at a time </p>

<p><strong>How do I light more than one LED at a time?</strong></p>

<pre><code>/*
TinyDuino Edge LED Demo

April 9 2014, by Ben Rose

This example code is in the public domain.

http://www.tiny-circuits.com

*/

void setup()
{
  LedOn(0);//Pass a zero to turn all LEDs off
}

void loop()
{
  for(int i=1;i&lt;16;i++){
    LedOn(i);
    delay(20);
  };
  for(int i=16;i&gt;1;i--){
    LedOn(i);
    delay(20);
  };
}

void LedOn(int ledNum)
{
  for(int i=5;i&lt;10;i++){
    pinMode(i, INPUT);
    digitalWrite(i, LOW);
  };
  if(ledNum&lt;1 || ledNum&gt;16) return;
  char highpin[16]={5,6,5,7,6,7,6,8,5,8,8,7,9,7,9,8};
  char lowpin[16]= {6,5,7,5,7,6,8,6,8,5,7,8,7,9,8,9};
  ledNum--;
  digitalWrite(highpin[ledNum],HIGH);
  digitalWrite(lowpin[ledNum],LOW);
  pinMode(highpin[ledNum],OUTPUT);
  pinMode(lowpin[ledNum],OUTPUT);
}
</code></pre>
 -1: <p><a href="https://i.stack.imgur.com/dHQgl.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/dHQgl.png" alt="enter image description here"></a></p>

<p>This is your circuit.</p>

<p>I think you can take it from here by looking at the diagram, but please note that e.g. 1 0 0 0 0 will light up 3 and 1, so be careful.</p>

<p>To show more than one, turn on multiple LEDs in rapid succession. It will give the effect that more than one are on. This is known as multiplexing.</p>

<p><strong>Update:</strong></p>

<p>After Googling around, I understood it better. I also wrote this code.</p>

<pre><code>int IO1 = 50;
int IO2 = 48;
int IO3 = 46;
int IO4 = 44;
int IO5 = 41;
int del = 1000;

void setup() {

  pinMode(IO1, INPUT);
  pinMode(IO2, INPUT);
  pinMode(IO3, INPUT);
  pinMode(IO4, INPUT);
  pinMode(IO5, INPUT);
  Serial.begin(9600);
}

// the loop routine runs over and over again forever:
void loop() {
    displayLED(1);
    delay(del);
    displayLED(2);
    delay(del);
    displayLED(3);
    delay(del);
    displayLED(4);
    delay(del);
    displayLED(5);
    delay(del);
    displayLED(6);
    delay(del);
    displayLED(7);
    delay(del);
    displayLED(8);
    delay(del);
    displayLED(9);
    delay(del);
    displayLED(10);
    delay(del);
    displayLED(11);
    delay(del);
    displayLED(12);
    delay(del);
    displayLED(13);
    delay(del);
    displayLED(14);
    delay(del);
    displayLED(15);
    delay(del);
    displayLED(16);
    delay(del);// light up LEDS 1, 2 and 3.
}

void displayLED(int a){
    clear();
    if (a == 1){o(1); o(2); h(1); l(2); Serial.println('1');}
    if (a == 2){o(1); o(2); l(1); h(2); Serial.println('2');}
    if (a == 3){o(1); o(3); h(1); l(3); Serial.println('3');}
    if (a == 4){o(1); o(3); l(1); h(3); Serial.println('4');}
    if (a == 5){o(2); o(3); h(2); l(3); Serial.println('5');}
    if (a == 6){o(2); o(3); l(2); h(3); Serial.println('6');}
    if (a == 7){o(2); o(4); h(2); l(4); Serial.println('7');}
    if (a == 8){o(2); o(4); l(2); h(4); Serial.println('8');}
    if (a == 9){o(1); o(4); h(1); l(4); Serial.println('9');}
    if (a == 10){o(1); o(4); l(1); h(4); Serial.println(10);}
    if (a == 11){o(3); o(4); l(3); h(4); Serial.println(11);}
    if (a == 12){o(3); o(4); h(3); l(4); Serial.println(a);}
    if (a == 13){o(3); o(5); l(3); h(5); Serial.println(a);}
    if (a == 14){o(3); o(5); h(3); l(5); Serial.println(a);}
    if (a == 15){o(4); o(5); l(4); h(5); Serial.println(a);}
    if (a == 16){o(4); o(5); h(4); l(5); Serial.println(a);}

}

void clear(){pinMode(IO1, INPUT);
  pinMode(IO2, INPUT);
  pinMode(IO3, INPUT);
  pinMode(IO4, INPUT);
  pinMode(IO5, INPUT);}

void o(int o){
    if (o == 1){pinMode(IO1, OUTPUT);}
    if (o == 2){pinMode(IO2, OUTPUT);}
    if (o == 3){pinMode(IO3, OUTPUT);}
    if (o == 4){pinMode(IO4, OUTPUT);}
    if (o == 5){pinMode(IO5, OUTPUT);}
}

void h(int l){
    if (l == 1){digitalWrite(IO1, HIGH);}
    if (l == 2){digitalWrite(IO2, HIGH);}
    if (l == 3){digitalWrite(IO3, HIGH);}
    if (l == 4){digitalWrite(IO4, HIGH);}
    if (l == 5){digitalWrite(IO5, HIGH);}
}

void l(int h){
    if (h == 1){digitalWrite(IO1, LOW);}
    if (h == 2){digitalWrite(IO2, LOW);}
    if (h == 3){digitalWrite(IO3, LOW);}
    if (h == 4){digitalWrite(IO4, LOW);}
    if (h == 5){digitalWrite(IO5, LOW);}
}
</code></pre>
