A variable-color region (106) of a tennis-playing structure of an information-presentation structure extends to an exposed surface (102) at a surface zone (112), normally appears along it as a principal color, and includes impact-sensitive and color-change components (182 and 184). A segment (192) of the impact-sensitive component responds to an object (104), typically a tennis ball, impacting the zone at an object-contact area (116) by providing an impact effect if the impact meets threshold impact criteria. A segment (194) of the color-change component responds to the impact effect by causing an impact-dependent portion (138) of the variable-color region to temporarily appear along a closely matching print area (118) of the zone as changed color materially different from the principal color. The zone adjoins a serviceline (34), the centerline (36), a sideline (30), or a baseline (28) to help determine whether a tennis ball impacted the surface “in” or “out”.