A cleaver grid. I tip my hat to anyone who can get the Lincoln connection though.

The Lincoln connection was the only one I got! ;-)

I managed it, though there was ample guesswork. I'm skeptical of "the 3" as an item in that group; seems too arbitrary. "The rubicon" and "Hexadecimal" were my ways in, and the "Candles" herring stopped me for a long time until I figured out was "Sulfur" was about.

The connections were too obscure for me.

Struggled only the rubicon one for me

Tough one. 2/10 for me after only finding the signals group, though I should have identified a couple more. Agree that 'the 3' feels a little tenuous. The Lincoln connection is clever.