We were talking about early Christians.
A friend, who is well-versed in Bible and Biblical stories, told me how they used the Fish sign as a secret password to recognise each other when Christianity was still considered a dangerous extremist sect and Christians were persecuted. I've always thought of it simply as a reference to the bread and fish miracle. But it turns out there's more to it.
You meet someone who you think might be one of yours. You put a dot in the sand with a big toe. The person standing opposite you would look at it and draw a curving line around the dot. You look at it and, with his foot, draw another curving line. They join up near the dot and cross at the other and, thus forming a representation of the Fish.
I decided to try it in Pages and here is what I got.
Click on the Shapes menu in the Toolbar of your document and choose the circle from the menu. Reduce it to the size of a dot.
Click on the Shapes menu in the Toolbar of your document and choose the pen tool in the top right corner.
Draw the first line by clicking in the document, then drag, let go to make the second dot, then drag again, let go and double-click on the last dot to finish the line.
Adjust the curve as you like by dragging the midpoints, they appear automatically as you hover the cursor over the line.
In the Inspector side pane make it thicker, change colour (here it is Mocha), and add shadow.
Repeat the above to draw the second line. And you get a lovely looking Fish sign.
Keep it in your document, make a screenshot or export to PDF to reuse elsewhere.