The toastangle has no inventor because it was never invented — it was discovered.
These objects have always had the shape; they were waiting for the name.
Standard
Bread, end sliceThe cross-section of a tin loaf — the shape that gave it its name.
Standard / Leaning
TombstoneThe classic upright stone. Standard subtype, occasionally Leaning with age.
Standard
Norman doorwayRomanesque architecture's go-to entrance. Often built as an arch but rendered as a toastangle by molding.
Sharp
Vintage television setThe 1960s console TV. Rounded glass tube framed by a wooden cabinet.
Splayed Standard
MailboxThe American curbside mailbox. A Splayed Standard toastangle on its side.
Sharp Standard
SIM cardNotch in the corner aside, the basic outline is a Sharp Standard toastangle.
Sharp Standard
Smartphone silhouetteMost modern phones. Sharp Standard at low aspect ratio.
Standard
Car side windowEspecially on coupes and older sedans. The shoulder mediates the A-pillar.
Splayed
Loaf panCross-section of a standard bread tin. The reason your slice is a toastangle.
Standard
Old radio cabinetBakelite-era tabletop radios. The dome housed the speaker grille.
Saddle
Bathtub, side profileThe Saddle subtype in domestic form. Walls rise, rim dips, basin holds water.
Saddle
Drainage channelEngineered Saddle. The downward top curve is the design — water collects in the dip.
Inverse Saddle
Ornate planterThe Inverse Saddle in stylized form. Walls tuck inward, basin dips for soil.
Disjointed Saddle
Asymmetric basin sculptureA Disjointed Saddle. One shoulder in, one shoulder out, top dipping between.
Standard (high τ)
Gothic round trefoil doorwayA Standard toastangle with high τ. The side lobes are the shoulders; the top lobe is the dome; the jambs are the sides. Drawn for eight centuries. Never formally identified as a toastangle until now.
Gallery images to be sourced from Unsplash and Pexels (commercial use, no attribution required).
SVG outlines shown until photographs are added.