I've tried that but it didn't go very far. Focusing on the line or lines makes it abstract, and people start focusing on the lines rather than on price (like the Darvas Box), and price movement is where it's at, not what sort of line the movement creates. Learning to trade via lines becomes analogous to learning how to play the piano by painting numbers on the keys.
So after several years of futzing with various kinds of lines, I focused on the tick, i.e., the transaction, and for whatever reason people begin to understand. And once one begins to understand, the fear begins to evaporate. And once the fear evaporates, one can get down to business.
Just for clarity - I meant the line which is the price. - not demand lines, trend lines, horizontal lines.
For those who can watch the tick line that fine, for other even a 5min line of the close (or a series of three lines close, high, low) to see the flow and extremes.
Its always and interesting issue of what makes something click for different people, and maybe the abstract works for some, of for others its a narrative they can relate to, and you are spot on - you need to get to the essence of something to eliminate that fear (of loss, or being right or wrong, of mummys wrath or whatever) however its done.
You have a lot of experience in teaching others and I so I defer to you. Personally I relate more to abstract ideas so I thought it a suggestion. Everyone needs to find their own ways of seeing the world.
(its kind of fascinating in its own right and for those interested check out 'threshold concepts' http://www.etl.tla.ed.ac.uk/docs/ETLreport4.pdf --- totally off topic but worth 15mins of reading just for the cooking example)